Internet
"The Internet, sometimes called simply "the Net," is a worldwide system of computer networks - a network of networks in which users at any one computer can, if they have permission, get information from any other computer (and sometimes talk directly to users at other computers)."
Types of Internet Connections
Analog (up to 56k):
Also called dial-up access, it is both economical and slow. Using a modem connected to your PC, users connect to the Internet when the computer dials a phone number (which is provided by your ISP) and connects to the network. Dial-up is an analog connection because data is sent over an analog, public telephone network. The modem converts received analog data to digital and vise versa. Because dial-up access uses normal telephone lines the quality of the connection is not always good and data rates are limited. Typical Dial-up connection speeds range from 2400 bps to 56 Kbps.
ISDN:
Integrated services digital network (ISDN) is an international communications standard for sending voice, video, and data over digital telephone lines or normal telephone wires. Typical ISDN speeds range from 64 Kbps to 128 Kbps.
B-ISDN:
Broadband ISDN is similar in function to ISDN but it transfers data over fiber optic telephone lines, not normal telephone wires. SONET is the physical transport backbone of B-ISDN. Broadband ISDN has not been widely implemented.
DSL:
DSL is also called an always on connection because it uses existing 2-wire copper telephone line connected to the premise and will not tie up your phone as a dial-up connection does. There is no need to dial-in to your ISP as DSL is always on. The two main categories of DSL for home subscribers are called ADSL and SDSL.
ADSL:
ADSL is the most commonly deployed types of DSL in North America. Short for asymmetric digitaland from 16 to 640 Kbps when sending data (known as the upstream rate). ADSL requires a special ADSL modem.
SDSL:
SDSL is still more common in Europe. Short forsymmetric digital subscriber line, a technology that allows more data to be sent over existing copper telephone lines (POTS). SDSL supports data rates up to 3 Mbps. SDSL works by sending digital pulses in the high-frequency area of telephone wires and can not operate simultaneously with voice connections over the same wires. SDSL requires a special SDSL modem. SDSL is called symmetric because it supports the same data rates for upstream and downstream traffic.
VDSL:
Very High DSL (VDSL) is a DSL technology that offers fast data rates over relatively short distances — the shorter the distance, the faster the connection rate. All types of DSL technologies are collectively referred to as xDSL. xDSL connection speeds range from 128 Kbps to 8 Mbps.
Cable:
Through the use of a cable modem you can have a broadband Internet connection that is designed to operate over cable TV lines. Cable Internet works by using TV channel space for data transmission, with certain channels used for downstream transmission, and other channels for upstream transmission. Because the coaxial cable used by cable TV provides much greater bandwidth than telephone lines, a cable modem can be used to achieve extremely fast access. Cable speeds range from 512 Kbps to 20 Mbps.
Wireless Internet Connections:
Wireless Internet, or wireless broadband is one of the newest Internet connection types. Instead of using telephone or cable networks for your Internet connection, you use radio frequency bands. Wireless Internet provides an always-on connection which can be accessed from anywhere — as long as you geographically within a network coverage area. Wireless access is still considered to be relatively new, and it may be difficult to find a wireless service provider in some areas. It is typically more expensive and mainly available in metropolitan areas.
T-1 Lines:
T-1 lines are a popular leased line option for businesses connecting to the Internet and for Internet Service Providers (ISPs) connecting to the Internet backbone. It is a dedicated phone connection supporting data rates of 1.544Mbps. A T-1 line actually consists of 24 individual channels, each of which supports 64Kbits per second. Each 64Kbit/second channel can be configured to carry voice or data traffic. Most telephone companies allow you to buy just one or some of these individual channels. This is known as as fractional T-1 access.
Bonded T-1:
A bonded T-1 is two or more T-1 lines that have been joined (bonded) together to increase bandwidth. Where a single T-1 provides approximately 1.5Mbps, two bonded T1s provide 3Mbps or 46 channels for voice or data. Two bonded T-1s allow you to use the full bandwidth of 3Mbps where two individual T-1s can still only use a maximum of 1.5Mbps at one time. To be bonded the T-1 must run into the same router at the end, meaning they must run to the same ISP. T-1 Lines support speeds of 1.544 Mbps. Fractional T-1 speeds are 64 Kbps per channel (up to 1.544 Mbps), depending on number of leased channels. Typical Bonded T-1 (two bonded T-1 lines) speed is around 3 Mbps. T-3 Lines:
T-3 lines are dedicated phone connections supportingdata rates of about 43 to 45 Mbps. It too is a popular leased line option. A T-3 line actually consists of 672 individual channels, each of which supports 64 Kbps. T-3 lines are used mainly by Internet Service Providers (ISPs) connecting to the Internet backbone and for the backbone itself. Typical T-3 supports speeds ranging from 43 to 45 Mbps.
Satellite:
Internet over Satellite (IoS) allows a user to access the Internet via a satellite that orbits the earth. A satellite is placed at a static point above the earth's surface, in a fixed position. Because of the enormous distances signals must travel from the earth up to the satellite and back again, IoS is slightly slower than high-speed terrestrial connections over copper or fiber optic cables. Typical Internet over Satellite connection speeds (standard IP services) average around 492 up to 512 Kbps.
To Find Information:
We can use the Internet to find information about almost anything, using Internet search engines such as Google and Yahoo. However, we must carefully check the source (website) and quality of the information. An example of good source of general information is wikipedia.org
File Sharing:
A file can be put on a “Shared Location” or onto a File Server for instant use by colleagues. Mirror servers and peer-to-peer networks can be used to ease the load of data transfer.
Communication and Social Networking:
Internet chat and instant messaging systems allow people to stay in touch in a convenient way while working at their computers. Messages can be sent and received instantly. In addition, these systems also allow file transfer, as well as voice and video contact. Social networking websites allow people to stay in touch with friends and family, and knowing their activities by viewing their profiles. The concept of a social networking website is to store people’s profiles and connecting them between one and another. A personal profile can include pictures and videos to be shared
Remote Access:
Computer users can easily connect to other computers and information stores around the world using the internet. The access can be done with or without security, authentication and encryption, depending on the needs. Remote access is encouraging new methods of working from home and information sharing in many businesses. Using Virtual Private Network (VPN), a businessman can use a remote desktop session to access his PC in the other side of the world.
VoIP:
VoIP (Voice over Internet Protocol) started from an optional two-way voice chat provided by some of the instant messaging systems that started around the year 2000. The benefit of VoIP is that it can be free or cost much less than a normal telephone call, because the Internet carries that voice traffic. VoIP is surely a cheap solution for long distance call"An intranet is a private computer network that uses Internet protocols and network connectivity to securely share any part of an organization's information or operational systems with its employees."
Features Of Intranet
Sometimes the term refers only to the organization's internal website, but often it is a more extensive part of the organization's computer infrastructure and private websites are an important component and focal point of internal communication and collaboration.
An intranet is built from the same concepts and technologies used for the Internet, such as clients and servers running on the Internet Protocol Suite (TCP/IP). Any of the well known Internet protocols may be found in an intranet, such as HTTP (web services), SMTP (e-mail), and FTP (file transfer).
Intranets differ from extranets in that the former are generally restricted to employees of the organization while extranets may also be accessed by customers, suppliers, or other approved parties. Extranets extend a private network onto the Internet with special provisions for access, authorization and authentication.
Intranets are being used to deliver tools and applications, e.g., collaboration (to facilitate working in groups and teleconferencing) or sophisticated corporate directories, sales and Customer relationship management tools, project management etc., to advance productivity.
Intranets are also being used as corporate culture-change platforms. For example, large numbers of employees discussing key issues in an intranet forum application could lead to new ideas in management, productivity, quality, and other corporate issues.
Implications of Intranet
Following are some general examples of information or processes that might be available on an intranet to serve various departments.
fundamental publications to all employees. Benefits, 401 k tracking, job applications, and an employee directory are just a few examples. A company newsletter and employee newsgroups or chat boards are other opportunities an intranet affords.
Sales Department:
One of the most productive uses of an intranet is interactive multimedia training. Sales reports, forecasts and goals, marketing strategies and geographic saturation are all tools the intranet can keep available at the click of a mouse. Profiles of potential new markets or clients, and information on potential competing markets can also be helpful to sales staff in designing better sales models.
Accounting Department:
Requisition requests on an intranet will save time, resources and money. Pages within an intranet can be password protected to limit employee access, or administratively controlled. Payroll, receivables/payables, and budget reports are all processes that can reside on the intranet.
Information Systems:
Data warehousing access, departmental software development applications, and network support can be invaluable uses of an intranet. Intranet support itself with FAQs and interactive tutorials for virtually any purpose or department, allow employees to teach themselves, minimizing training investment. Security information and technical resources are also common uses of an intranet.
Executive Branch:
Bottom line information like quarterly profit/loss reports, stock market analysis, tax and legal information, and merger or partnership information can all be neatly provided on an intranet. Meeting minutes, appointment calendars and key profiles (employees, companies or clients) can also reside here.Extranet
"An extranet is a private network that uses Internet protocols, network connectivity, and possibly the public telecommunication system to securely share part of an organization's information or operations with suppliers, vendors, partners, customers or other businesses." It has also been described as a "state of mind" in which the Internet is perceived as a way to do business with a pre approved set of other companies' business-to-business (B2B), in isolation from all other Internet users. In
contrast, business-to-consumer (B2C) involves known server(s) of one or more companies, communicating with previously unknown consumer users.
Features of Extranet
It has also been described as a "state of mind" in which the Internet is perceived as a way to do business with a pre approved set of other companies' business-to-business (B2B), in isolation from all other Internet users. In contrast, business-to-consumer (B2C) involves known server(s) of one or more companies, communicating with previously unknown consumer users
An extranet can be understood as an intranet mapped onto the public Internet or some other transmission system not accessible to the general public, but is managed by more than one company's administrator(s). For example, military networks of different security levels may map onto a common military radio transmission system that never connects to the Internet.
Implications of Extranet
During the late 1990s and early 2000s, several industries started to use the term "extranet" to describe central repositories of shared data made accessible via the web only to authorized members of particular work groups.
For example, in the construction industry, project teams could login to and access a 'project extranet' to share drawings and documents make comments, issue requests for information, etc. In 2003 in the United Kingdom, several of the leading vendors formed the Network of Construction Collaboration Technology Providers, or NCCTP, to promote the technologies and to establish data exchange standards between the different systems. The same type of construction-focused technologies has also been developed in the United States, Australia, Scandinavia, Germany and Belgium, among others. Some applications are offered on Software as a Service (SaaS) basis by vendors functioning as Application service providers (ASPs).
Specially secured extranets are used to provide virtual data room services to companies in several sectors (including law and accountancy). There are a variety of commercial extranet applications, some of which are for pure file management, and others which include broader collaboration and project management tools also there are exist a variety of Open Source extranet applications and modules, which can be integrated into other online collaborative applications such as Content Management Systems.
Traditionally, the term neural network had been used to refer to a network or circuit of biological neurons. The modern usage of the term often refers to artificial neural networks, which are composed of artificial neurons or nodes."
Thus the term has two distinct usages:
Biological neural networks
are made up of real biological neurons that are connected or functionally-related in the peripheral nervous system or the central nervous system. In the field of neuroscience, they are often identified as groups of neurons that perform a specific physiological function in laboratory analysis. Artificial neural networks
are made up of interconnectingartificial neurons (programming constructs that mimic the properties of biological neurons). Artificial neural networks may either be used to gain an understanding of biological neural networks, or for solving artificial intelligence problems without necessarily creating a model of a real biological system. The real biological nervous system is highly complex including some features which may seem superfluous to the understanding of the working of artificial networks.
Implications of Neural Network
The tasks to which artificial neural networks are applied tend to fall within the following broad categories:
Function approximation, or regression analysis, including time series prediction and modeling.
Classification, including pattern and sequence recognition, novelty detection and sequential decision making.
Data processing, including filtering, clustering, blind signal separation and compression.
Application areas include system identification and control (vehicle control, process control), game-playing and decision making (backgammon, chess, racing), pattern recognition (radar systems, face identification, object recognition, etc.), sequence recognition (gesture, speech, handwritten text recognition), medical diagnosis, financial applications, data mining (or knowledge discovery in databases, "KDD"), visualization and e-mail spam filtering.
