Company Profile
Chartered Technologies (Pvt.) Ltd. integrates satellite into your
network applications in order to provide reliable, high-quality
connection to the edge of the network, broadcast one-to-many,
and support bandwidth-hungry applications.It provide searvices in Pakistan, Afganista and
Oman.
Chartered Technologies (Pvt.) Ltd. offers a complete range of
Information Technology services to match the needs of today’s forward
thinking global businesses: For online booking plz visit
http://www.charteredtechnologies.com/onlinebooking.html
• Satellite based Communication
• iDirect Networks & Remotes
• Satellite Capacity.
• DVB Solutions
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Address Suit No. 1, Block No. 3, St.22, F-8/2 Islamabad, Pakistan
Telephone (+92-51) 2853647 - 2853734
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URL www.charteredtechnologies.net
Dubai Office
Address P.O Box. 181258. Dubai, UAE
Telephone +971-4-262 8889
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Peshawar Office
Address Office No.3, Second Floor, Mir Nisar Plaza, Nishterabad Chowk, Peshawar City.Telephone +091-5594157
TECHNOLOGIES News
Why Is The Internet Sometimes So Slow? Internet 'Black Holes' May Be To Blame
You're trying to log on to a Web site and it's not working. You try again and again. But persistence doesn't pay off. The site you want is inexplicably, frustratingly, out of
reach.The other computer might just be turned off, but the causes could be more mysterious. At any given moment, a proportion of computer traffic ends up being routed into information black holes. These are situations where a path between two computers does exist, but messages -- a request to visit a Web site, an outgoing e-mail -- get lost along the way.
A University of Washington system named Hubble looks for these black holes and maps them on a Web site, providing an ever-changing constellation of the Internet's weak points.
The Hubble map lets visitors see a map of problems worldwide or type in a specific Web page or network address to check its status. The work is being presented in San Francisco at the Usenix Symposium on Networked Systems Design and Implementation.
"There's an assumption that if you have a working Internet connection then you have access to the entire Internet," said Ethan Katz-Bassett, a UW doctoral student in computer science and engineering. "We found that's not the case."
The project is named for the Hubble Space Telescope, which can observe black holes in deep space, because the UW tool performs a similar function for the maze of routers and fiber-optic cables that make up the Internet. In fact, research on the Internet's structure and performance is sometimes described as Internet astronomy.
"It's the idea of peering into the depths of something and trying to figure out what's going on, without having direct access," Katz-Bassett said.
The UW researchers send test messages around the world to look for computers that can be reached from some but not all of the Internet, a situation known as partial reachability. Short communication blips are ignored; a problem has to register in two consecutive 15-minute trials to appear on the site. A test last fall found that more than 7 percent of computers worldwide experienced this type of error at least once during a three-week period.
"When we started this project, we really didn't expect to find so many problems," said Arvind Krishnamurthy, a UW research assistant professor of computer science and engineering and Katz-Bassett's doctoral adviser. "We were very surprised by the results we got."
Now the team has created an online global map, updated every 15 minutes, showing locations currently experiencing problems. Hubble shows a flag on the area that's experiencing problems and lists the numerical address for the group of computers affected. Each address typically describes a few hundred to a few thousand individual computers. Hubble also reports what percentage of test probes was successful, and how long each problem has persisted.
Clicking a flag reveals which locations were and were not able to reach that machine. Future versions of Hubble will try to pinpoint the cause of each black hole.
Hubble's virtual eye on the Internet is made possible by PlanetLab, a shared worldwide network of academic, industrial and government computers. The UW researchers use about 100 PlanetLab computers in about 40 countries to send virtual probes to computers around the globe. Hubble monitors about 90 percent of the Internet, researchers said.
The new map can satisfy a frustrated user's idle curiosity about why a Web site is not loading. But the tool promises to be especially useful to professional network operators who keep the Internet running smoothly. Right now, when a computer network experiences a problem the administrator typically turns to online discussion boards.
"You would think that the network operators of Internet service providers would have access to better data," said Katz-Bassett. "That's not the case. The general approach has been to mail something out to a listserv and say, 'Hey, can you try this and see if you have a problem?'"
In a world that relies increasingly on online communication for e-mail, banking, television, phone calls, medical information and emergency communications, researchers want to make the overall network more transparent and more reliable.
"We want to give operators a way to tell what's going on quicker, catch problems quicker and solve them quicker," Krishnamurthy said.
This research received funding from the National Science Foundation.
Adapted from materials provided by University of Washington
Does The Internet Really Influence Suicidal Behavior?
People searching the Internet for information about suicide methods are most likely to come across sites that encourage suicide rather than sites offering help and support, finds a study in the British Medical Journal. Media reporting of suicide and its portrayal on television are known to influence suicidal behaviour, particularly the choice of method used, but little is known about the influence of the internet.
Recent reports in the popular press have highlighted the existence and possible influence of internet sites that promote suicide and web forums that may encourage suicide in young people.
But despite these recent controversies, the ease with which these sites may be found on the internet has not been systematically documented nor the kind of information they contain been described.
Researchers from the Universities of Bristol, Oxford and Manchester set out to replicate a typical search that might be undertaken by a person looking for instructions and information about methods of suicide using the four most popular search engines--Google, Yahoo, MSN, and Ask--and 12 simple search terms.They analysed the first ten sites from each search, giving a total of 480 hits.
Altogether 240 different sites were found and just under half of these provided some information about methods of suicide. Almost a fifth of hits (90) were for dedicated suicide sites, of which half were judged to be encouraging, promoting, or facilitating suicide.
Sixty-two (13%) sites focused on suicide prevention or offered support and 59 (12%) sites actively discouraged suicide.
Almost all dedicated suicide and factual information sites provided information about methods of suicide. But, a fifth (21%) of support and prevention sites and over half (55%) of academic or policy sites, and all news reports of suicides also provided information about methods.
Overall, Google and Yahoo retrieved the highest number of dedicated suicide sites, whereas MSN had the highest number of prevention or support sites and academic or policy sites.
In addition, the three most frequently occurring sites were all pro-suicide, whereas the information site Wikipedia was fourth. All top four sites evaluated methods of suicide including detailed information about speed, certainty, and the likely amount of pain associated with each method.
However, there is currently no regulation of suicide sites in the UK because they are not illegal.
Self-regulation by internet providers and use of filtering software by parents to block sites are the main approaches to reducing potential harm from suicide sites. However, efforts to remove some of the most detailed technical descriptions of suicide methods may be easily circumvented, say the authors.
They conclude that service providers might pursue website optimisation strategies to maximise the likelihood that sites aimed at preventing suicide are preferentially sourced by people seeking information about suicide methods rather than potentially harmful sites.
Tiny Radio Antennas' Under Skin Could Act As Remote Sensors Of Humans' Emotional, Physiological StateTiny Radio Antennas' Under Skin Could Act As Remote Sensors Of Humans' Emotional, Physiological State
Scientists at the department of Applied Physics of the Hebrew University of Jerusalem have discovered a method for remote sensing of the physiological and emotional state of human beings.
The researchers believe the discovery could theoretically help remotely monitor medical patients, evaluate athletic performance, diagnose disease and remotely sense the level of excitation – which could have significant implications for technology in the biomedical engineering, anti-terror and security technology fields.
The key is in the surprising shape of human sweat ducts. Professors Yuri Feldman and Aharon Agranat together with Dr. Alexander Puzenko, Dr. Andreas Caduff and PhD student Paul Ben-Ishai have discovered that the human skin is structured as an array of minute antennas that operate in the “Sub Terahertz” frequency range.
This discovery is based on investigations of the internal layers of the skin that were undertaken using a new imaging technique called “Optical Coherent Tomography”. Images produced by this technique revealed that the sweat ducts, which are the tubes that lead the sweat from the sweat gland to the surface of the skin, are shaped as tiny coils. Similar helical structures with much larger dimensions have been used widely in as antennas in wireless communication systems. This made the investigators consider the possibility that the sweat ducts could behave like tiny helical antennas as well.
In a series of experiments, the team measured the electromagnetic radiation reflected from the palm skin at the frequency range between 75GHz and 110GHz. It was found that the level of the reflected intensity depends strongly on the level of activity of the perspiration system. In particular, it was found that the reflected signal is very different if measured in a subject that was relaxed, and if measured in a subject following intense physical activity.
In a second set of measurements it was found that during the period of return to the relaxed state, the reflected signal was strongly correlated with changes in the blood pressure and the pulse rate that were measured simultaneously.
The initial results of the research were published last week in the prestigious scientific journal The Physical Review Letters. The publication aroused significant interest among scientists, physicians and science writers.
The researchers emphasize however, that the research is still in its initial stages and as they “sail in unsheltered water” it will take some time before the full significance of the research is understood and its technological potential is fully evaluated.
The invention has been patented and commercialized by Yissum, the technology transfer company of the Hebrew University of Jerusalem.
HP Breakthrough Could Spawn Computers That Don't Forget
Until recently, there were three known fundamental circuit elements: the resistor, the capacitor and the inductor. Since the 1970s, engineers have theorized a fourth -- the memristor -- and now HP Labs researchers have proven its existence. The memristor could be used to boost computing efficiency.
Researchers at HP Labs have proven the existence of the "memristor," a component of electrical circuits that could lead to computer systems with memories that never forget, the company announced Wednesday.
The memristor -- short for "memory resistor" -- was previously only theorized to be the fourth fundamental circuit element in electrical engineering. In the April 30 edition of the journal Nature, however, HP (NYSE: HPQ) researchers presented both a mathematical model and a physical example of one.
Consuming far less power than current systems, computers based on the memristor would not need to be booted up and could associate information in a way much the way the human brain does.