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SETI@home ("SETI at home") is a distributed computing project using Internet-connected computers, hosted by the Space Sciences Laboratory, at the University of California, Berkeley, in the United States. SETI is an acronym for the Search for Extra-Terrestrial Intelligence. SETI@home was released to the public on May 17, 1999.••• Scientific Research The goal of SETI@home is to detect intelligent life outside Earth. SETI@home searches for possible evidence of radio transmissions from extraterrestrial intelligence using data from the Arecibo radio telescope. The software searches for four signals: The process is somewhat like tuning a radio to various channels, and looking at the signal strength meter. If the strength of the signal goes up, that gets attention. More technically, it involves a lot of digital signal processing, mostly discrete Fourier transforms at various chirp rates and durations. Results While the project has not found any conclusive signs of extraterrestrial intelligence, it has identified several candidate spots for further analysis. The most significant candidate signal to date was announced on September 1, 2004, named Radio source SHGb02+14a. Seth Shostak (2004), a prominent SETI figure, has stated that he expects to get a conclusive signal and proof of alien contact between 2020 and 2025, based on the Drake equation. While the project hasn't yet officially reached its goals, it did prove to the scientific community that distributed computing projects using Internet-connected computers can work and even compete with the largest supercomputers. Technology
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Statistics With over 5.2 million participants worldwide, the project is the distributed computing project with the most participants to date. Since its launch on May 17, 1999, the project has logged over two million years of aggregate computing time. On September 26, 2001, SETI@home had performed a total of 1021 floating point operations. It is acknowledged by the Guinness World Records as the largest computation in history (Newport 2005). With over 900,000 computers in the system, SETI@home has the ability to compute over 250 TFLOPS (as of April 17 2006). For comparison, Blue Gene (one of the the world's fastest supercomputers) computes 280 TFLOPS. Project futures There are future plans to get data from the Parkes Observatory in Australia to analyse the southern hemisphere. Competitive aspect SETI@home users quickly started to compete with one another in an effort to process the maximum number of work units. Teams were formed to combine the efforts of individual users. The competition continued, and grew larger, with the introduction of BOINC. As with any competition, numerous attempts have been made to 'cheat' the system and claim credit for work that has not been performed. To combat cheats, the organisers send out each work unit multiple times and only stop sending out the same work unit when they receive back results from two or more different users that exactly agree. Some users have installed and run SETI@home on computers at their workplaces — an act known as 'Borging', after the assimilation-driven Borg of Star Trek. In some cases, users have mis-utilized company resources to gain work-unit results — with at least one individual getting fired for running SETI@home on an enterprise production system (Foreman 2004). Other users collected large quantities of equipment together at home to create "SETI farms", which typically consist of a number of computers consisting of only a motherboard, CPU, RAM and power supply that are arranged on shelves as diskless workstations running either Linux or Windows 98 SE "headless" (without a video card). Threats to the project Like any project of indefinite duration, there are factors that may result in its eventual termination. Some of these are detailed below: Participants not prepared for the long term Even before the project went live, people were commenting that many people might have false expectations of the likelihood of any one project finding an extraterrestrial intelligence, or of one being found within a specific amount of time. Their fear would be that this would be bad public relations for SETI as a whole. Although it is not clear how many people have become disillusioned as a result of unreasonable expectations, there have certainly been vociferous cases. Also, many participants are participating for reasons other than the science and will be affected by changes in fashion. Alternative distributed computing projects When the project was launched there were few alternative ways of donating computer time to research projects. However, now there are a lot more options, and therefore SETI@home has to compete with other projects. As different people have different value systems, some will (for example) prefer projects with a relatively high chance of benefitting humanity in the short term, while others will avoid these because they are more likely to be associated with commercial profit. Yet there are now nonprofit organizations working for these humanitarian goals, such as the World Community Grid, which likewise has teams and a points system, yet focuses on AIDS treatments and proteome folding. More restrictive computer use policies in businesses As of 16 October 2005, approximately one third of the processing for the non-BOINC version of the software was performed on work or school based machines (SETI@home, 2005). As a lot of these computers will give reduced privileges to ordinary users, it is possible that much of this has been done by network administrators themselves. A number of administrators have also expressed concerns about the automatic software updating in BOINC workunits. To some extent, this may be offset by better connectivity to home machines. Funding There is currently no government funding for SETI research, and private funding is always limited. Berkeley Space Science Lab has found ways of working with small budgets and the project has received donations allowing it to go well beyond its original planned duration, but it still has to compete for limited funds with other SETI projects and other space sciences projects. Security concerns Carrigan (2003) has advanced the theory that SETI@home could expose Earth's internet to an extraterrestrial virus. There are concerns by some that digital signals received could be malicious, and able to spread on Earth's internet. However, it is extremely improbable that the analysis of electromagnetic data using mathematical functions (mainly Discrete Fourier transforms and Gaussian function) can generate viral code. It would be a potential concern if SETI@home's goal was to decode and interpret an identified signal, although it would still remain extremely unlikely. In addition, most computer scientists agree that writing a virus would require knowledge of the computer systems in use, and because of the extremely short time that wireless networks powerful enough to broadcast into space (see satellite internet) have been around, these signals would not have reached any but the closest of stars. There are also concerns that human-made computer viruses could cause false-positives in the SETI@home project.* Unofficial clients A number of individuals and companies made unofficial changes to the distributed part of the software to try and produce faster results, but this compromised the integrity of all the results (Molnar 2000). As a result, the software had to be updated to make it easier to detect such changes. BOINC allows unofficial clients and relies more on cross-checking.* Other distributed computing projects Distributed computing is also being used for medical research, such as to searching for AIDS treatments and in protein folding projects. Since the switch to the BOINC platform however, users can divide work between projects, choosing to give only a percentage of CPU time to each. However, competition exists between BOINC and the World Community Grid, which uses a United Devices client by default. The World Community Grid, like BOINC, enables access to as many projects as the platform supports. World Community Grid is more centralized and easier to manage than BOINC, at the cost of fewer choices. World Community Grid currently also runs a BOINC client.WCG BOINC See also | |||||||||||
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