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Saturday, November 21, 2009
wikipedia
For Wikipedia's non-encyclopedic visitor introduction, see Wikipedia:About.
 | |
|---|---|
 Screenshot of Wikipedia's multilingual portal. | |
| URL | http://www.wikipedia.org/ |
| Slogan | The free encyclopedia that anyone can edit. |
| Commercial? | No |
| Type of site | Internet encyclopedia project |
| Registration | Optional |
| Available language(s) | 240 active editions (271 in total)[1] |
| Content license | Creative Commons Attribution/ Share-Alike 3.0 and GFDL dual-license |
| Owner | Wikimedia Foundation (non-profit) |
| Created by | Jimmy Wales, Larry Sanger[2] |
| Launched | January 15, 2001 |
| Alexa rank | 6[3] |
| Current status | Perpetual work-in-progress[4] |
Critics of Wikipedia accuse it of systemic bias and inconsistencies (including undue weight given to popular culture),[11] and allege that it favors consensus over credentials in its editorial process.[12] Its reliability and accuracy are also claimed to be an issue.[13] Other criticisms center on its susceptibility to vandalism and the addition of spurious or unverified information,[14] though scholarly work suggests that vandalism is generally short-lived,[15][16] and an investigation in Nature found that the material they compared came close to the level of accuracy of Encyclopædia Britannica and had a similar rate of "serious errors".[17] These claims have been disputed by Encyclopædia Britannica;[18] Nature in turn published a rebuttal to Britannica's objections.[19]
Wikipedia's departure from the expert-driven style of the encyclopedia building mode and the large presence of unacademic contents have been noted several times. When Time magazine recognized You as its Person of the Year for 2006, acknowledging the accelerating success of online collaboration and interaction by millions of users around the world, it cited Wikipedia as one of several examples of Web 2.0 services, along with YouTube, MySpace, and Facebook.[20] Some noted the importance of Wikipedia not only as an encyclopedic reference but also as a frequently updated news resource because of how quickly articles about recent events appear.[21][22]
Contents[hide] |
History
Main article: History of Wikipedia
Wikipedia began as a complementary project for Nupedia, a free online English-language encyclopedia project whose articles were written by experts and reviewed under a formal process. Nupedia was founded on March 9, 2000, under the ownership of Bomis, Inc, a web portal company. Its main figures were Jimmy Wales, Bomis CEO, and Larry Sanger, editor-in-chief for Nupedia and later Wikipedia. Nupedia was licensed initially under its own Nupedia Open Content License, switching to the GNU Free Documentation License before Wikipedia's founding at the urging of Richard Stallman.[23]Larry Sanger and Jimmy Wales founded Wikipedia.[24][25] While Wales is credited with defining the goal of making a publicly editable encyclopedia,[26][27] Sanger is usually credited with the strategy of using a wiki to reach that goal.[28] On January 10, 2001, Larry Sanger proposed on the Nupedia mailing list to create a wiki as a "feeder" project for Nupedia.[29] Wikipedia was formally launched on January 15, 2001, as a single English-language edition at www.wikipedia.com,[30] and announced by Sanger on the Nupedia mailing list.[26] Wikipedia's policy of "neutral point-of-view"[31] was codified in its initial months, and was similar to Nupedia's earlier "nonbiased" policy. Otherwise, there were relatively few rules initially and Wikipedia operated independently of Nupedia.[26]
Citing fears of commercial advertising and lack of control in a perceived English-centric Wikipedia, users of the Spanish Wikipedia forked from Wikipedia to create the Enciclopedia Libre in February 2002.[34] Later that year, Wales announced that Wikipedia would not display advertisements, and its website was moved to wikipedia.org.[35] Various other projects have since forked from Wikipedia for editorial reasons. Wikinfo does not require a neutral point of view and allows original research. New Wikipedia-inspired projects – such as Citizendium, Scholarpedia, Conservapedia, and Google's Knol[36] – have been started to address perceived limitations of Wikipedia, such as its policies on peer review, original research, and commercial advertising.
Nature of Wikipedia
Editing model
Most importantly, when changes to an article are made, they become available immediately before undergoing any review, no matter if they contain an error, are somehow misguided, or even patent nonsense. The German edition of Wikipedia is an exception to this rule: it has been testing a system of maintaining "stable versions" of articles,[41] to allow a reader to see versions of articles that have passed certain reviews. The English edition of Wikipedia plans to trial a related approach.[42][43] Another proposal is the use of software to create "trust ratings" for individual Wikipedia contributors and using those ratings to determine which changes will be made visible immediately.[44]
Articles in Wikipedia are organized roughly in three ways according to: development status, subject matter and the access level required for editing. The most developed state of articles is called "featured article": they are precisely ones that someday get featured in the main page of Wikipedia.[48][49] Researcher Giacomo Poderi found that articles tend to reach the FA status via intensive works of few editors, and that the categories such as history, media, music and warfare have higher ratio of featured articles than those such as computing, mathematics, language & linguistics and philosophy & psychology, casting a doubt to the equation "more edits equal higher quality." In 2007, in preparation for producing a print version, the English-language Wikipedia introduced an assessment scale against which the quality of articles is judged;[50] other editions have also adopted this.
In 2008, two researchers theorized that the growth of Wikipedia is sustainable.[51]
Attacks on the encyclopedia
The Wikipedia is constantly edited by a wide variety of people with a wide variety of motives, and inevitably some try to subvert the integrity of the encyclopedia. Research suggests that, for the most part, these attacks are dealt with quickly.Vandalism
The open nature of the editing model has been central to most criticism of Wikipedia. For example, a reader of an article cannot be certain that it has not been vandalized with the insertion of false information or the removal of essential information. Former Encyclopaedia Britannica editor-in-chief Robert McHenry once described this by saying:[52]and called Wikipedia a "faith-based encyclopedia."[53]The user who visits Wikipedia to learn about some subject, to confirm some matter of fact, is rather in the position of a visitor to a public restroom. It may be obviously dirty, so that he knows to exercise great care, or it may seem fairly clean, so that he may be lulled into a false sense of security. What he certainly does not know is who has used the facilities before him.
This incident led to policy changes on the site, specifically targeted at tightening up the verifiability of all biographical articles of living people.
Spam, agenda pushing, and trolls
Wikipedia's open structure inherently makes it an easy target for Internet trolls, spamming, and those with an agenda to push.[45][56] The addition of political spin to articles by organizations including members of the U.S. House of Representatives and special interest groups[14] has been noted,[57] and organizations such as Microsoft have offered financial incentives to work on certain articles.[58] These issues have been parodied, notably by Stephen Colbert in The Colbert Report.[59]For example, in August 2007, the website WikiScanner began to trace the sources of changes made to Wikipedia by anonymous editors without Wikipedia accounts. The program revealed that many such edits were made by corporations or government agencies changing the content of articles related to them, their personnel or their work.[60]
Defences
The Wikipedia has a complex multi-layered defence against these kinds of attacks. These include users checking pages and edits, computer programs ('bots') that are carefully designed to try to detect them and fix them automatically (or semi-automatically), blocks on the creation of links to particular websites, blocks on edits from particular accounts, IP addresses or address ranges.For heavily attacked pages, particular articles can be semi-protected so that only well established accounts can edit them,[61] or for particularly contentious cases, locked so that only administrators are able to make changes.[62]
Coverage of topics
| Wiki |
| The Beatles |
| Michael Jackson |
| Favicon |
| YouTube |
| Wikipedia |
| Barack Obama |
| Deaths in 2009 |
| United States |
| Current events portal |
| World War II |
| Transformers |
| Slumdog Millionaire |
| Lil Wayne |
| Adolf Hitler |
| India |
| Transformers 2 |
| Scrubs (TV series) |
See also: Notability in Wikipedia
As an encyclopedia building project, Wikipedia seeks to create a summary of all human knowledge: all of topics covered by a conventional print encyclopedia plus any other "notable" (therefore verifiable by published sources) topics, which are permitted by unlimited disk space.[64] In particular, it contains materials that some people, including Wikipedia editors,[65] may find objectionable, offensive, or pornographic.[66] It was made clear that this policy is not up for debate, and the policy has sometimes proved controversial. For instance, in 2008, Wikipedia rejected an online petition against the inclusion of Muhammad's depictions in its English edition, citing this policy. The presence of politically sensitive materials in Wikipedia had also led the People's Republic of China to block access to parts of the site.[67] (See also: IWF block of Wikipedia)Content in Wikipedia is subject to the laws (in particular copyright law) in Florida, where Wikipedia servers are hosted, and several editorial policies and guidelines that are intended to reinforce the notion that Wikipedia is an encyclopedia. Each entry in Wikipedia must be about a topic that is encyclopedic and thus is worthy of inclusion. A topic is deemed encyclopedic if it is "notable"[68] in the Wikipedia jargon; i.e., if it has received significant coverage in secondary reliable sources (i.e., mainstream media or major academic journals) that are independent of the subject of the topic. Second, Wikipedia must expose knowledge that is already established and recognized.[69] In other words, it must not present, for instance, new information or original works. A claim that is likely to be challenged requires a reference to reliable sources. Within the Wikipedia community, this is often phrased as "verifiability, not truth" to express the idea that the readers are left themselves to check the truthfulness of what appears in the articles and to make their own interpretations.[70] Finally, Wikipedia does not take a side.[71] All opinions and viewpoints, if attributable to external sources, must enjoy appropriate share of coverage within an article.[72] Wikipedia editors as a community write and revise those policies and guidelines[73] and enforce them by deleting, annotating with tags, or modifying article materials failing to meet them. (See also deletionism and inclusionism)[74][75]
As of September 2009[update], Wikipedia articles cover about half a million places on Earth. However, research conducted by the Oxford Internet Institute has shown that the geographic distribution of articles is highly uneven. Most articles are written about North America, Europe, and East Asia, with very little coverage of large parts of the developing world, including most of Africa.[76]
Quality
Critics argue that non-expert editing undermines quality. Because contributors usually rewrite small portions of an entry rather than making full-length revisions, high- and low-quality content may be intermingled within an entry. Historian Roy Rosenzweig noted: "Overall, writing is the Achilles' heel of Wikipedia. Committees rarely write well, and Wikipedia entries often have a choppy quality that results from the stringing together of sentences or paragraphs written by different people."[77]Reliability
As a consequence of the open structure, Wikipedia "makes no guarantee of validity" of its content, since no one is ultimately responsible for any claims appearing in it.[78] Concerns have been raised regarding the lack of accountability that results from users' anonymity,[79] the insertion of spurious information[80], vandalism, and similar problems.Wikipedia has been accused of exhibiting systemic bias and inconsistency;[13] additionally, critics argue that Wikipedia's open nature and a lack of proper sources for much of the information makes it unreliable.[81] Some commentators suggest that Wikipedia is generally reliable, but that the reliability of any given article is not always clear.[12] Editors of traditional reference works such as the Encyclopædia Britannica have questioned the project's utility and status as an encyclopedia.[82] Many university lecturers discourage students from citing any encyclopedia in academic work, preferring primary sources;[83] some specifically prohibit Wikipedia citations.[84] Co-founder Jimmy Wales stresses that encyclopedias of any type are not usually appropriate as primary sources, and should not be relied upon as authoritative.[85]
However, an investigation reported in the journal Nature in 2005 suggested that for scientific articles Wikipedia came close to the level of accuracy of Encyclopædia Britannica and had a similar rate of "serious errors."[17] These claims have been disputed by Encyclopædia Britannica.[18]
Andrew Lih, author of the 2009 book The Wikipedia Revolution, notes: "A wiki has all its activities happening in the open for inspection... Trust is built by observing the actions of others in the community and discovering people with like or complementary interests.”[86] Economist Tyler Cowen writes, "If I had to guess whether Wikipedia or the median refereed journal article on economics was more likely to be true, after a not so long think I would opt for Wikipedia." He comments that many traditional sources of non-fiction suffer from systemic biases. Novel results are over-reported in journal articles, and relevant information is omitted from news reports. However, he also cautions that errors are frequently found on Internet sites, and that academics and experts must be vigilant in correcting them.[87]
In February 2007, an article in The Harvard Crimson newspaper reported that some of the professors at Harvard University include Wikipedia in their syllabi, but that there is a split in their perception of using Wikipedia.[88] In June 2007, former president of the American Library Association Michael Gorman condemned Wikipedia, along with Google,[89] stating that academics who endorse the use of Wikipedia are "the intellectual equivalent of a dietitian who recommends a steady diet of Big Macs with everything". He also said that "a generation of intellectual sluggards incapable of moving beyond the Internet" was being produced at universities. He complains that the web-based sources are discouraging students from learning from the more rare texts which are either found only on paper or are on subscription-only web sites. In the same article Jenny Fry (a research fellow at the Oxford Internet Institute) commented on academics who cite Wikipedia, saying that: "You cannot say children are intellectually lazy because they are using the Internet when academics are using search engines in their research. The difference is that they have more experience of being critical about what is retrieved and whether it is authoritative. Children need to be told how to use the Internet in a critical and appropriate way."[89]
Community
The Wikipedia community has established "a bureaucracy of sorts", including "a clear power structure that gives volunteer administrators the authority to exercise editorial control."[90][91][92] Wikipedia's community has also been described as "cult-like",[93] although not always with entirely negative connotations,[94] and criticized for failing to accommodate inexperienced users.[95] Editors in good standing in the community can run for one of many levels of volunteer stewardship; this begins with "administrator",[96][97] a group of privileged users who have the ability to delete pages, lock articles from being changed in case of vandalism or editorial disputes, and block users from editing. Despite the name, administrators do not enjoy any special privilege in decision-making; instead they are mostly limited to making edits that have project-wide effects and thus are disallowed to ordinary editors, and to ban users making disruptive edits (such as vandalism).[98][99]
In a 2003 study of Wikipedia as a community, economics Ph.D. student Andrea Ciffolilli argued that the low transaction costs of participating in wiki software create a catalyst for collaborative development, and that a "creative construction" approach encourages participation.[103] In his 2008 book, The Future of the Internet and How to Stop It, Jonathan Zittrain of the Oxford Internet Institute and Harvard Law School’s Berkman Center for Internet & Society cites Wikipedia's success as a case study in how open collaboration has fostered innovation on the web.[104] A 2008 study found that Wikipedia users were less agreeable and open, though more conscientious, than non-Wikipedia users.[105][106] A 2009 study suggested there was "evidence of growing resistance from the Wikipedia community to new content."[107]
The Wikipedia Signpost is the community newspaper on the English Wikipedia,[108] and was founded by Michael Snow, an administrator and the current chair of the Wikimedia Foundation board of trustees.[109] It covers news and events from the site, as well as major events from sister projects, such as Wikimedia Commons.[110]
Notable users of Wikipedia include film critic Roger Ebert[111][112] and University of Maryland physicist Robert L. Park.[113]
about tea
QUALITY TEA
QUALITY LIFE
if you cold, tea will warm you
if you are too heated, it will cool you
if you are depressed, it will cheer you
if you are excited, it will calm you
gladstone 1865
Sunday, November 8, 2009
penemu mesin diesel
Rudolf Diesel : Penemu Mesin Diesel
Jakarta-RRI-Online,
Rudolf Diesel lahir di Paris Perancis tanggal 18 Maret 1858. Rudolf merupakan pencipta mesin bertekanan panas yang dikenal dengan mesin diesel.
Setelah lulus dari Politeknik Munich, Rudolf bekerja sebagai teknisi mesin pendingin pada Perusahaan mesin pembuat es Linde di Paris.
Tahun 1890 dia pindah ke Berlin untuk mengelola perusahaan yang bergerak dalam bidang teknik perkantoran. Meskipun telah bekerja di kantoran, minatnya pada rancangan mesin tak pernah hilang dari ingatannya. Diesel mengerjakan sebuah gagasannya untuk membuat mesin panas yang efisien saat luang. Rancangan itu baru terwujud di tahun 1892 dan hak patennya keluar setahun kemudian.
Rancangan Diesel sangat efisiensi dibandingkan mesin yang ada pada saat itu. Mesin diesel tidak memerlukan pembakaran luar dengan mencampur udara dan bahan bakar yang ada di dalam mesin. Lebih dari itu, mesin ini dilengkapi dengan penekan udara dalam mesin silinder dan memanaskannya hingga ke mesin, tekanan udara tersebut akan berhubungan dengan udara yang ada sebelumnya diakhir tempo tekanan, tekanan inilah yang memanaskan mesin.
Hasilnya mesin diesel lebih kecil dan lebih ringan daripada mesin sebelumnya yang biasa digunakan pada kendaraan serta tidak menggunakan bahan bakar sebagai sumber pembakaran.
Diesel ingin melihat rancangannya menjadi nyata, sebuah mesin yang handal. Untuk menyempurnakannya dia membutuhkan perusahaan besar untuk bekerjasama sebagai penyandang dana dalam pembuat mesin tersebut.
Setelah memperoleh rekan bisnisnya, dia langsung memproduksi sebuah mesin ujicoba dan prototipenya berhasil dibuat tahun 1893. Pada tes awal, hasilnya membahayakan, Diesel hampir tewas ketika salah satu mesinnya meledak.
Namun hasil tes tersebut membuktikan bahwa bahan bakar dapat terbakar tanpa percikan bunga api. Dia bekerja dengan cekatan untuk memperbaiki model mesinnya dan berhasil melakukan ujicoba di tahun 1897.
Setahun kemudian, Diesel menjadi orang kaya raya. Mesin ciptaannya secara teoritis 75 persen lebih efisien sementara mesin lama memiliki tingkat efisien 10 persen dibandingkan mesin uap. Mesin diesel langsung digunakan sebagai tenaga untuk mobil, truk, dan kapal laut. Selain itu juga digunakan sebagai sumber tenaga listrik, jalur-jalur pipa, penyiram tumbuhan, pertambangan, pabrik-pabrik dan ladang minyak. Bahkan sampai saat ini mesin diesel masih dipakai dan menjadi konsep dasar bagi penemu-penemu lainnya.
Mesin diesel memiliki pengaruh besar dalam era revolusi industri, menyediakan tenaga yang lebih efisien dan lebih murah bagi beraneka ragam industri di seluruh dunia. Karena mesinnya tidak memerlukan pembakaran batu bara, sehingga perusahaan alat transportasi kereta dan kapal laut dapat menghemat banyak uang. tentu saja hal tersebut tidak menguntungkan bagi industri pertambangan batu bara dan peranannya pun mulai berkurang.
Pada 29 September 1913, Diesel menghilang dari kapal laut yang ditumpanginya menuju London. Mayatnya baru ditemukan dipantai beberapa hari kemudian. Misteri di balik kematiannya masih misterius sampai sekarang. Sebagian percaya mungkin dia bunuh diri, sementara lainnya berspekulasi bahwa dia dibunuh oleh pengusaha batu bara.
Jakarta-RRI-Online,
Rudolf Diesel lahir di Paris Perancis tanggal 18 Maret 1858. Rudolf merupakan pencipta mesin bertekanan panas yang dikenal dengan mesin diesel.
Setelah lulus dari Politeknik Munich, Rudolf bekerja sebagai teknisi mesin pendingin pada Perusahaan mesin pembuat es Linde di Paris.
Tahun 1890 dia pindah ke Berlin untuk mengelola perusahaan yang bergerak dalam bidang teknik perkantoran. Meskipun telah bekerja di kantoran, minatnya pada rancangan mesin tak pernah hilang dari ingatannya. Diesel mengerjakan sebuah gagasannya untuk membuat mesin panas yang efisien saat luang. Rancangan itu baru terwujud di tahun 1892 dan hak patennya keluar setahun kemudian.
Rancangan Diesel sangat efisiensi dibandingkan mesin yang ada pada saat itu. Mesin diesel tidak memerlukan pembakaran luar dengan mencampur udara dan bahan bakar yang ada di dalam mesin. Lebih dari itu, mesin ini dilengkapi dengan penekan udara dalam mesin silinder dan memanaskannya hingga ke mesin, tekanan udara tersebut akan berhubungan dengan udara yang ada sebelumnya diakhir tempo tekanan, tekanan inilah yang memanaskan mesin.
Hasilnya mesin diesel lebih kecil dan lebih ringan daripada mesin sebelumnya yang biasa digunakan pada kendaraan serta tidak menggunakan bahan bakar sebagai sumber pembakaran.
Diesel ingin melihat rancangannya menjadi nyata, sebuah mesin yang handal. Untuk menyempurnakannya dia membutuhkan perusahaan besar untuk bekerjasama sebagai penyandang dana dalam pembuat mesin tersebut.
Setelah memperoleh rekan bisnisnya, dia langsung memproduksi sebuah mesin ujicoba dan prototipenya berhasil dibuat tahun 1893. Pada tes awal, hasilnya membahayakan, Diesel hampir tewas ketika salah satu mesinnya meledak.
Namun hasil tes tersebut membuktikan bahwa bahan bakar dapat terbakar tanpa percikan bunga api. Dia bekerja dengan cekatan untuk memperbaiki model mesinnya dan berhasil melakukan ujicoba di tahun 1897.
Setahun kemudian, Diesel menjadi orang kaya raya. Mesin ciptaannya secara teoritis 75 persen lebih efisien sementara mesin lama memiliki tingkat efisien 10 persen dibandingkan mesin uap. Mesin diesel langsung digunakan sebagai tenaga untuk mobil, truk, dan kapal laut. Selain itu juga digunakan sebagai sumber tenaga listrik, jalur-jalur pipa, penyiram tumbuhan, pertambangan, pabrik-pabrik dan ladang minyak. Bahkan sampai saat ini mesin diesel masih dipakai dan menjadi konsep dasar bagi penemu-penemu lainnya.
Mesin diesel memiliki pengaruh besar dalam era revolusi industri, menyediakan tenaga yang lebih efisien dan lebih murah bagi beraneka ragam industri di seluruh dunia. Karena mesinnya tidak memerlukan pembakaran batu bara, sehingga perusahaan alat transportasi kereta dan kapal laut dapat menghemat banyak uang. tentu saja hal tersebut tidak menguntungkan bagi industri pertambangan batu bara dan peranannya pun mulai berkurang.
Pada 29 September 1913, Diesel menghilang dari kapal laut yang ditumpanginya menuju London. Mayatnya baru ditemukan dipantai beberapa hari kemudian. Misteri di balik kematiannya masih misterius sampai sekarang. Sebagian percaya mungkin dia bunuh diri, sementara lainnya berspekulasi bahwa dia dibunuh oleh pengusaha batu bara.
tips merawat mobil bermesin diesel
perawatan mobil bermesin diesel menurut sebagian orang dianggap tidak mudah dan mahal padahal kenyataannya tidak seperti itu, alasannya karena bila dipergunakan untuk jarak jauh mesin diesel akan semakin bertenaga dan irit. untuk itu ad beberapa kiat mudah yang harus dilakukan untuk menjaga agar mobil bermesin diesel tetap dapat aman melaju:1. panaskan dahulu mesinnya jangan terburu-buru unutk menjalan mesin tanpa pemanasan sedikitnya lima menit
2. tangki jangan sampai kosong
3. filter udara harus rajin dibersihkan minimal 20 km
4. filter solar juga harus diperhatikan kebersihannya
5. ganti oli setiap 5000 km
6. setiap pagi harus membuang air dari saringan solar dan ganti setelah 16.000 km
7. perbaikan injection pump harus di bengkel khusus mesin diesel
8. accu, kabel2 harus tetap di perhatikan
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