An intranet is a local area network (LAN) used internally in an organisation to facilitate communication and access to information that is sometimes access-restricted. Sometimes the term refers only to the most visible service, the internal web site. The same concepts and technologies of the Internet such as clients and servers running on the Internet protocol suite are used to build an intranet. HTTP and other internet protocols are commonly used as well, especially FTP and email. There is often an attempt to use internet technologies to provide new interfaces with corporate 'legacy' data and information systems.
There does not necessarily have to be any access from the organisations's internal network to the internet itself. Where there is, there will be a firewall with a gateway through which all access takes place. Traffic going through the gateway can be monitored by the organisation's security department. This means that organisations that allow their staff internet access can normally determine which internet web sites are being viewed, block access to specific sites they don't want them to see (such as pornographic sex sites), and even trace offenders who persistently attempt to view them. They can also block certain types of web content (such as objects) which they consider a particular security risk.
Where external email access is provided, known sources of spam and specific types of email attachment can be blocked by the organisation. It should also be noted that emails sent and received this way can be required to be produced by the organisation in the event of legal action against it by a third party.
Tuesday, September 20, 2005
Friday, September 16, 2005
radar
Although both are not exactly new, social software like blogs and wikis are turning people's heads all over the Internet and even in the mainstream media. Of the two, blogs are more known and have grabbed more attention on the news with politics and in magazines like Time. Blogs were covered in an earlier On The Radar column here.
What in the world is a wiki? Unlike "blog" which is short for weblog, the term "wiki" was created in 1995 by a programmer from Oregon named Ward Cunningham. He got the term from wiki wiki, which means "quick" in Hawaiian. According to Webopedia.com, a wiki is:
"A collaborative Web site comprised of the perpetual collective work of many authors. Similar to a blog in structure and logic, a wiki allows anyone to edit, delete or modify content that has been placed on the Web site using a browser interface, including the work of previous authors. In contrast, a blog, typically authored by an individual, does not allow visitors to change the original posted material, only add comments to the original content."
What in the world is a wiki? Unlike "blog" which is short for weblog, the term "wiki" was created in 1995 by a programmer from Oregon named Ward Cunningham. He got the term from wiki wiki, which means "quick" in Hawaiian. According to Webopedia.com, a wiki is:
"A collaborative Web site comprised of the perpetual collective work of many authors. Similar to a blog in structure and logic, a wiki allows anyone to edit, delete or modify content that has been placed on the Web site using a browser interface, including the work of previous authors. In contrast, a blog, typically authored by an individual, does not allow visitors to change the original posted material, only add comments to the original content."
rada]
Although both are not exactly new, social software like blogs and wikis are turning people's heads all over the Internet and even in the mainstream media. Of the two, blogs are more known and have grabbed more attention on the news with politics and in magazines like Time. Blogs were covered in an earlier On The Radar column here.
What in the world is a wiki? Unlike "blog" which is short for weblog, the term "wiki" was created in 1995 by a programmer from Oregon named Ward Cunningham. He got the term from wiki wiki, which means "quick" in Hawaiian. According to Webopedia.com, a wiki is:
"A collaborative Web site comprised of the perpetual collective work of many authors. Similar to a blog in structure and logic, a wiki allows anyone to edit, delete or modify content that has been placed on the Web site using a browser interface, including the work of previous authors. In contrast, a blog, typically authored by an individual, does not allow visitors to change the original posted material, only add comments to the original content."
What in the world is a wiki? Unlike "blog" which is short for weblog, the term "wiki" was created in 1995 by a programmer from Oregon named Ward Cunningham. He got the term from wiki wiki, which means "quick" in Hawaiian. According to Webopedia.com, a wiki is:
"A collaborative Web site comprised of the perpetual collective work of many authors. Similar to a blog in structure and logic, a wiki allows anyone to edit, delete or modify content that has been placed on the Web site using a browser interface, including the work of previous authors. In contrast, a blog, typically authored by an individual, does not allow visitors to change the original posted material, only add comments to the original content."
radar
recently spent some time with an excellent Wiki guide: Peter Theony, the developer of TWiki, a widely used open source Wiki implementation. Peter developed TWiki in the late ‘90s in a classic moment of “scratch the itch” software development. He had been hired by a company to be an engineering manager but a reorg detoured him into a support manager role. In that role, he needed to build a dynamic knowledge base for customer support and he found the concept of the Wiki as a knowledge base platform intriguing.
Thus TWiki was born and several years later, TWiki is being actively and enthusiastically used as the platform for everything from document management to project planning and corporate knowledge bases at corporations as varied as Disney, Yahoo, British Telecom, and SAP (Profile, Products, Articles). TWiki.org publishes detailed case studies of these organizations with gushing testimonials from employees who gladly publish their names and job titles. This is clearly the real deal.
Superficially, the Wiki concept is scary to many CIOs and CTOs. The hallmarks of the Wiki environment — organic, easy to change by anyone, constantly evolving, aggressively open, unstructured — are a far cry from the relative rigidity of more traditional knowledge management systems. When we started blogging IT documentation internally at InfoWorld, there was an explosion of documentation not because of the novelty of blogging (frankly, documentation just isn’t fun), but because the documentation was easy to create and people were able to quickly realize the benefits of knowledge-sharing. The Wiki environment is even more informal than blogging, but what you lose in fine-grained control, you gain in information flow.
After my conversation with Peter, I was psyched up to give TWiki a spin, so I logged into our intranet server planning to set TWiki up and check it out. Guess what? It had already been installed months ago by our IT manager. I took this as yet another reason that I needed to pay attention. Worthwhile IT innovation is nearly always a bottom-up affair. If you were a naysayer about the Internet, Linux, or even Weblogs, embracing the Wiki might be your chance to beat your staffers to the punch at last. Next week, I’ll go into more specific detail on how a Wiki implementation such as TWiki can be used in the enterprise
Thus TWiki was born and several years later, TWiki is being actively and enthusiastically used as the platform for everything from document management to project planning and corporate knowledge bases at corporations as varied as Disney, Yahoo, British Telecom, and SAP (Profile, Products, Articles). TWiki.org publishes detailed case studies of these organizations with gushing testimonials from employees who gladly publish their names and job titles. This is clearly the real deal.
Superficially, the Wiki concept is scary to many CIOs and CTOs. The hallmarks of the Wiki environment — organic, easy to change by anyone, constantly evolving, aggressively open, unstructured — are a far cry from the relative rigidity of more traditional knowledge management systems. When we started blogging IT documentation internally at InfoWorld, there was an explosion of documentation not because of the novelty of blogging (frankly, documentation just isn’t fun), but because the documentation was easy to create and people were able to quickly realize the benefits of knowledge-sharing. The Wiki environment is even more informal than blogging, but what you lose in fine-grained control, you gain in information flow.
After my conversation with Peter, I was psyched up to give TWiki a spin, so I logged into our intranet server planning to set TWiki up and check it out. Guess what? It had already been installed months ago by our IT manager. I took this as yet another reason that I needed to pay attention. Worthwhile IT innovation is nearly always a bottom-up affair. If you were a naysayer about the Internet, Linux, or even Weblogs, embracing the Wiki might be your chance to beat your staffers to the punch at last. Next week, I’ll go into more specific detail on how a Wiki implementation such as TWiki can be used in the enterprise
radar
According to Wikipedia — a Wiki itself — a Wiki is a Web site that allows any user to add content, but also allows that content to be edited by any other user more easily than a blog. The term “Wiki” can also be used to refer to the software used to drive a Wiki.
I recently spent some time with an excellent Wiki guide: Peter Theony, the developer of TWiki, a widely used open source Wiki implementation. Peter developed TWiki in the late ‘90s in a classic moment of “scratch the itch” software development. He had been hired by a company to be an engineering manager but a reorg detoured him into a support manager role. In that role, he needed to build a dynamic knowledge base for customer support and he found the concept of the Wiki as a knowledge base platform intriguing.
I recently spent some time with an excellent Wiki guide: Peter Theony, the developer of TWiki, a widely used open source Wiki implementation. Peter developed TWiki in the late ‘90s in a classic moment of “scratch the itch” software development. He had been hired by a company to be an engineering manager but a reorg detoured him into a support manager role. In that role, he needed to build a dynamic knowledge base for customer support and he found the concept of the Wiki as a knowledge base platform intriguing.
radar
The traditional band names originated as code-names during World War II and are still in military and aviation use throughout the world in the 21st century. They have been adopted in the United States by the IEEE, and internationally by the ITU. Most countries have additional regulations to control which parts of each band are available for civilian or military use.
Other users of the radio spectrum, such as the broadcasting and electronic countermeasures (ECM) industries, have replaced the traditional military designations with their own systems.
Other users of the radio spectrum, such as the broadcasting and electronic countermeasures (ECM) industries, have replaced the traditional military designations with their own systems.
radar
In the common case where the transmitter and receiver are at the same location, Rt = Rr and the term Rt² Rr² can be replaced by R4, where R is the range. This yields:
This shows that the received power declines as the fourth power of the range, which means that the reflected power from distant targets is very, very small.
Note that the equation above is a simplification for vacuum without interference. In a real-world situation, pathloss effects should be considered, as well as other factors of the transmission medium.
Other mathematical developments in radar signal processing include time-frequency analysis (Weyl Heisenberg or wavelet), as well as the chirplet transform which makes use of the fact that radar returns from moving targets typically "chirp" (change their frequency as a function of time, as does the sound of a bird or bat).
This shows that the received power declines as the fourth power of the range, which means that the reflected power from distant targets is very, very small.
Note that the equation above is a simplification for vacuum without interference. In a real-world situation, pathloss effects should be considered, as well as other factors of the transmission medium.
Other mathematical developments in radar signal processing include time-frequency analysis (Weyl Heisenberg or wavelet), as well as the chirplet transform which makes use of the fact that radar returns from moving targets typically "chirp" (change their frequency as a function of time, as does the sound of a bird or bat).
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