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George W. Bush conducting a video tele-conference at Offutt Air Force Base
George W. Bush conducting a video tele-conference at Offutt Air Force Base

A videoconference (also known as a videoteleconference) is a set of interactive telecommunication technologies which allow two or more locations to interact via two-way video and audio transmissions simultaneously. George Walker Bush ( born July 6 1946 is the forty-third and current President of the United States. Technology is a broad concept that deals with a Species ' usage and knowledge of Tools and Crafts and how it affects a species' ability to control and adapt It has also been called visual collaboration and is a type of groupware. Collaborative software (also referred to as groupware or workgroup support systems) is software designed to help people involved in a common task achieve their It differs from videophone in that it is designed to serve a conference rather than individuals. A videophone, also known by the trademarked name Picturephone, is a Telephone which is capable of both audio and Video Duplex transmission

Contents

History

Videoconferencing uses telecommunications of audio and video to bring people at different sites together for a meeting. This can be as simple as a conversation between two people in private offices (point-to-point) or involve several sites (multi-point) with more than one person in large rooms at different sites. Besides the audio and visual transmission of meeting activities, videoconferencing can be used to share documents, computer-displayed information, and whiteboards.

Simple analog videoconferences could be established as early as the invention of the television. Television ( TV) is a widely used Telecommunication medium for sending ( Broadcasting) and receiving moving Images, either monochromatic Such videoconferencing systems consisted of two closed-circuit television systems connected via cable. Closed-circuit television ( CCTV) is the use of Video cameras to transmit a signal to a specific place limited set of monitors During the first manned space flights, NASA used two radiofrequency (UHF or VHF) links, one in each direction. Spaceflight is the use of Space technology to fly a Spacecraft into and through Outer space. The National Aeronautics and Space Administration ( NASA, ˈnæsə is an agency of the United States government, responsible for the nation's public space program Very high frequency (VHF is the Radio frequency range from 30 MHz to 300 MHz. TV channels routinely use this kind of videoconferencing when reporting from distant locations, for instance. Then mobile links to satellites using specially equipped trucks became rather common. This article is about artificial satellites For natural satellites also known as moons see Natural satellite.

Videoconferencing first demonstrated in 1968
Videoconferencing first demonstrated in 1968

This technique was very expensive, though, and could not be used for more mundane applications, such as telemedicine, distance education, business meetings, and so on, particularly in long-distance applications. Telemedicine is a rapidly developing application of Clinical medicine where medical information is transferred via telephone the Internet or other networks for the purpose of consulting Distance education, or distance learning, is a field of education that focuses on the Pedagogy and Andragogy, technology and instructional systems design Attempts at using normal telephony networks to transmit slow-scan video, such as the first systems developed by AT&T, failed mostly due to the poor picture quality and the lack of efficient video compression techniques. In Telecommunication, telephony (təˈlɛfəni or teh-LEH-fuh-nee encompasses the general use of equipment to provide voice communication over distances specifically Before proposing a merge request please see Talk and see if the merger you propose has recently been made and Video compression refers to reducing the quantity of Data used to represent video images and is a straightforward combination of Image compression and Motion The greater 1 MHz bandwidth and 6 Mbit/s bit rate of Picturephone in the 1970s also did not cause the service to prosper. A videophone, also known by the trademarked name Picturephone, is a Telephone which is capable of both audio and Video Duplex transmission

It was only in the 1980s that digital telephony transmission networks became possible, such as ISDN, assuring a minimum bit rate (usually 128 kilobits/s) for compressed video and audio transmission. Digital telephony is the use of digital electronics in the provision of digital Telephone services and systems In Telecommunications and Computing, bitrate (sometimes written bit rate, data rate or as a Variable R or f b The first dedicated systems, such as those manufactured by pioneering VTC firms, like PictureTel, started to appear in the market as ISDN networks were expanding throughout the world. Video teleconference systems throughout the 1990s rapidly evolved from highly expensive proprietary equipment, software and network requirements to standards based technology that is readily available to the general public at a reasonable cost. Finally, in the 1990s, IP (Internet Protocol) based videoconferencing became possible, and more efficient video compression technologies were developed, permitting desktop, or personal computer (PC)-based videoconferencing. In 1992 CU-SeeMe was developed at Cornell by Tim Dorcey et al. , IVS was designed at INRIA, VTC arrived to the masses and free services, web plugins and software, such as NetMeeting, MSN Messenger, Yahoo Messenger, SightSpeed, Skype and others brought cheap, albeit low-quality, VTC. Microsoft NetMeeting is a VoIP and multi-point Videoconferencing client included in many versions of Microsoft Windows (from Windows 95 OSR2 Yahoo! Messenger is an Advertisement -supported Instant messaging client and associated protocol provided by Yahoo!. SightSpeed is a Videoconferencing, VoIP and Instant messaging client for Microsoft Windows and Apple Macintosh Operating systems Skype (skaɪp is Software that allows users to make telephone calls over the Internet.

Technology

Dual plasma display videoconferencing system. The screen on the left is primarily used to show people during the conference or the user interface when setting up the call. The one on the right shows data in this case but can display a 2nd 'far site' in a multipoint call.
Dual plasma display videoconferencing system. The screen on the left is primarily used to show people during the conference or the user interface when setting up the call. The one on the right shows data in this case but can display a 2nd 'far site' in a multipoint call.

The core technology used in a videoteleconference (VTC) system is digital compression of audio and video streams in real time. The hardware or software that performs compression is called a codec (coder/decoder). Hardware is a general term that refers to the physical artifacts of a Technology. A codec is a device or program capable of encoding and/or decoding a Digital Data stream or signal. Compression rates of up to 1:500 can be achieved. The resulting digital stream of 1s and 0s is subdivided into labelled packets, which are then transmitted through a digital network of some kind (usually ISDN or IP). In Information technology, a packet is a formatted unit of Data carried by a Packet mode Computer network. Digital electronics are Electronics systems that use Digital signals Digital electronics are representations of Boolean algebra also see The use of audio modems in the transmission line allow for the use of POTS, or the Plain Old Telephone System, in some low-speed applications, such as videotelephony, because they convert the digital pulses to/from analog waves in the audio spectrum range. Modem (from mo dulator- dem odulator is a device that modulates an analog carrier signal to encode Digital information A videophone, also known by the trademarked name Picturephone, is a Telephone which is capable of both audio and Video Duplex transmission

The other components required for a VTC system include:

There are basically two kinds of VTC systems:

  1. Dedicated systems (manufactured by companies such as Sony, Tandberg, Polycom, and Radvision Ltd.) have all required components packaged into a single piece of equipment, usually a console with a high quality remote controlled video camera. A video camera is a Camera used for electronic Motion picture acquisition initially developed by the Television industry but now common in other applications Webcams ( web cameras) are small cameras (usually though not always Video cameras, whose images can be accessed using the World Wide Web, instant A visual display unit, often called simply a monitor or display, is a piece of Electrical equipment which displays images generated from the Video Television ( TV) is a widely used Telecommunication medium for sending ( Broadcasting) and receiving moving Images, either monochromatic For the Marty Friedman album see Loudspeaker (album A loudspeaker, speaker, or speaker system is an electroacoustical The Internet is a global system of interconnected Computer networks is a multinational conglomerate corporation headquartered in Minato Tokyo, Japan, and one of the world's largest Media conglomerates with Tandberg ( is a manufacturer of Video Encoders Multiplexers and Videoconferencing systems located in Oslo, Norway Polycom Inc is a manufacturer of Telepresence, Teleconferencing and Videoconferencing equipment RADVISION Ltd, founded in 1992 is a Nasdaq -traded company that provides products and technologies (developer toolkits for videoconferencing video telephony and the A remote control is an electronic device used for the remote operation of a Machine. These cameras can be controlled at a distance to pan left and right, tilt up and down, and zoom. They became known as PTZ cameras. The console contains all electrical interfaces, the control computer, and the software or hardware-based codec. Omnidirectional microphones are connected to the console, as well as a TV monitor with loudspeakers and/or a video projector. A video projector takes a Video signal and projects the corresponding image on a Projection screen using a lens system There are several types of dedicated VTC devices:
    1. Large group VTC are non-portable, large, more expensive devices used for large rooms and auditoriums.
    2. Small group VTC are non-portable or portable, smaller, less expensive devices used for small meeting rooms.
    3. Individual VTC are usually portable devices, meant for single users, have fixed cameras, microphones and loudspeakers integrated into the console.
  2. Desktop systems are add-ons (hardware boards, usually) to normal PCs[1], transforming them into VTC devices. A range of different cameras and microphones can be used with the board, which contains the necessary codec and transmission interfaces. Most of the desktops systems work with the H.323 standard. H323 is an umbrella Recommendation from the ITU Telecommunication Standardization Sector (ITU-T that defines the protocols to provide Audio-visual communication Videoconferences carried out via dispersed PCs are also known as e-meetings.

Echo cancellation

A fundamental feature of professional VTC systems is acoustic echo cancellation (AEC). The term Echo cancellation is used in Telephony to describe the process of removing echo from a voice communication in order to improve voice quality on AEC is an algorithm which is able to detect when sounds or utterances reenter the audio input of the VTC codec, which came from the audio output of the same system, after some time delay. In Mathematics, Computing, Linguistics and related subjects an algorithm is a sequence of finite instructions often used for Calculation If unchecked, this can lead to several problems including 1) the remote party hearing their own voice coming back at them (usually significantly delayed) 2) strong reverberation, rendering the voice channel useless as it becomes hard to understand and 3) howling created by feedback. Reverberation is the persistence of Sound in a particular space after the original sound is removed Echo cancellation is a processor-intensive task that usually works over a narrow range of sound delays.

Multipoint videoconferencing

Simultaneous videoconferencing among three or more remote points is possible by means of a Multipoint Control Unit (MCU). A Multipoint Control Unit (MCU is a device commonly used to bridge Videoconferencing connections This is a bridge that interconnects calls from several sources (in a similar way to the audio conference call). All parties call the MCU unit, or the MCU unit can also call the parties which are going to participate, in sequence. There are MCU bridges for IP and ISDN-based videoconferencing. There are MCUs which are pure software, and others which are a combination of hardware and software. An MCU is characterised according to the number of simultaneous calls it can handle, its ability to conduct transposing of data rates and protocols, and features such as Continuous Presence, in which multiple parties can be seen onscreen at once.

MCUs can be stand-alone hardware devices, or they can be embedded into dedicated VTC units.

Some systems are capable of multipoint conferencing with no MCU, stand-alone, embedded or otherwise. These use a standards-based H. 323 technique known as "decentralized multipoint", where each station in a multipoint call exchanges video and audio directly with the other stations with no central "manager" or other bottleneck. The advantages of this technique are that the video and audio will generally be of higher quality because they don't have to be relayed through a central point. Also, users can make ad-hoc multipoint calls without any concern for the availability or control of an MCU. This added convenience and quality comes at the expense of some increased network bandwidth, because every station must transmit to every other station directly.

Issues

Some observers [2] argue that two outstanding issues are preventing videoconferencing from becoming a standard form of communication, despite the ubiquity of videoconferencing-capable systems. These issues are:

  1. Eye Contact: It is known that eye contact plays a large role in conversational turn-taking, perceived attention and intent, and other aspects of group communication. [3] While traditional telephone conversations give no eye contact cues, videoconferencing systems are arguably worse in that they provide an incorrect impression that the remote interlocutor is avoiding eye contact. This issue is being addressed through research that generates a synthetic image with eye contact using stereo reconstruction. [4]
  2. Appearance Consciousness: A second problem with videoconferencing is that one is literally on camera, with the video stream possibly even being recorded. The burden of presenting an acceptable on-screen appearance is not present in audio-only communication. Early studies by Alphonse Chapanis found that the addition of video actually impaired communication, possibly because of the consciousness of being on camera.

The issue of eye-contact may be solved with advancing technology, and presumably the issue of appearance consciousness will fade as people become accustomed to videoconferencing.

Standards

The International Telecommunications Union (ITU) (formerly: Consultative Committee on International Telegraphy and Telephony (CCITT)) has three umbrellas of standards for VTC.

  1. ITU H.320 is known as the standard for public switched telephone networks (PSTN) or VTC over integrated services digital networks (ISDN) basic rate interface (BRI) or primary rate interface (PRI). H320 is an umbrella recommendation by the ITU-T for running Multimedia (Audio/Video/Data over ISDN based networks H. 320 is also used on dedicated networks such as T1 and satellite-based networks;
  2. ITU H.323 is known as a standard for transporting multimedia applications over LANs. This article is about artificial satellites For natural satellites also known as moons see Natural satellite. H323 is an umbrella Recommendation from the ITU Telecommunication Standardization Sector (ITU-T that defines the protocols to provide Audio-visual communication This same standard also applies to older implementations of voice over IP VoIP. Voice-over-Internet protocol ( VoIP, vɔɪp is a protocol optimized for the transmission of voice through the Internet In recent years, the IETF's Session Initiation Protocol (SIP) has gained considerable momentum in practice for these two services. The Session Initiation Protocol ( SIP) is a signalling protocol widely used for setting up and tearing down Multimedia Communication sessions ;
  3. ITU H.324 is the standard for transmission over POTS, or audio telephony networks. H324 is an ITU-T recommendation for voice, Video and Data transmission over regular analog Phone lines 3G-324M is a 3GPP implementation for video call on 3G mobile phones. 3G-324M is the 3GPP umbrella protocol for Video telephony in 3G mobile networks. The 3rd Generation Partnership Project ( 3GPP) is a collaboration between groups of telecommunications associations to make a globally applicable third generation ( 3G 3G is the third generation of mobile phone standards and Technology, superseding 2

In recent years, IP based videoconferencing has emerged as a common communications interface and standard provided by VTC manufacturers in their traditional ISDN-based systems. Business, government and military organizations still predominantly use H. 320 and ISDN VTC. Though, due to the price point and proliferation of the Internet, and broadband in particular, there has been a strong spurt of growth and use of H. 323, IP VTC. H. 323 has the advantage that it is accessible to anyone with a high speed Internet connection, such as DSL.

In addition, an attractive factor for IP VTC is that it is easier to set-up for use with a live VTC call along with web conferencing for use in data collaboration. Web conferencing is used to conduct live Meetings or Presentations over the Internet. Data conferencing refers to a communication session among two or more participants sharing computer data in real time These combined technologies enable users to have a much richer multimedia environment for live meetings, collaboration and presentations. Multimedia is media and content that utilizes a combination of different content forms.

Impact on the general public

High speed Internet connectivity has become more widely available at a reasonable cost and the cost of video capture and display technology has decreased. Consequently personal video teleconference systems based on a webcam, personal computer system, software compression and broadband Internet connectivity have become affordable for the general public. Also, the hardware used for this technology has continued to improve in quality, and prices have dropped dramatically. The availability of freeware (often as part of chat programs) has made software based videoconferencing accessible to many. Online chat can refer to any kind of Communication over the Internet, but is primarily meant to refer to direct one-on-one chat or Text-based group

For many years, futurists have envisioned a future where telephone conversations will take place as actual face-to-face encounters with video as well as audio. Sometimes it is simply not possible or practical to have a face-to-face meeting with two or more people. Sometimes a telephone conversation or conference call is adequate. Other times, an email exchange is adequate.

Videoconferencing adds another possible alternative, and can be considered when:

Deaf and hard of hearing individuals have a particular interest in the development of affordable high-quality videoconferencing as a means of communicating with each other in sign language. Deaf Culture is social group of people who consider Deafness to be a difference in human experience rather than a Disability. A sign language (also signed language) is a Language which instead of acoustically conveyed Sound patterns uses visually transmitted sign patterns Unlike Video Relay Service, which is intended to support communication between a caller using sign language and another party using spoken language, videoconferencing can be used between two signers. A Video Relay Service (VRS is a telecommunication service that allows Deaf, hard of hearing and speech-impaired individuals to communicate over the phone

Mass adoption and use of video conferencing is still relatively low, with the following often claimed as causes:

For these reasons many hardware systems are often used for internal corporate use only, as they are less likely to run into problems and lose a sale. An alternative is companies that hire out video conferencing equipped meeting rooms in cities around the world. Customers simply book the rooms and turn up for the meeting - everything else is arranged and support is readily available if anything should go wrong.

Impact on education

See also: Distance education

Videoconferencing provides students with the opportunity to learn by participating in a 2-way communication platform. Distance education, or distance learning, is a field of education that focuses on the Pedagogy and Andragogy, technology and instructional systems design Furthermore, teachers and lecturers from all over the world can be brought to classes in remote or otherwise isolated places. Students from diverse communities and backgrounds can come together to learn about one another. Students are able to explore, communicate, analyze and share information and ideas with one another. Through videoconferencing students can visit another part of the world to speak with others, visit a zoo, a museum and so on, to learn. These "virtual field trips" (see history of virtual learning environments) can bring opportunities to children, especially those in geographically isolated locations, or the economically disadvantaged. A Virtual learning environment (VLE is a system that creates an environment designed to facilitate teachers in the management of educational courses for their students especially Small schools can use this technology to pool resources and teach courses (such as foreign languages) which could not otherwise be offered.

Here are a few examples of how videoconferencing can benefit people around campus:

Impact on medicine and health

Videoconferencing is a very useful technology for telemedicine and telenursing applications, such as diagnosis, consulting, transmission of medical images, etc. Teleseminars are used to provide information Training, or promote or sell products to group of people interested in a particular topic Telemedicine is a rapidly developing application of Clinical medicine where medical information is transferred via telephone the Internet or other networks for the purpose of consulting Telenursing refers to the use of Telecommunications and Information technology for providing Nursing services in Health care whenever a Diagnosis is the identification by Process of elimination, of the nature of anything Medical imaging refers to the techniques and processes used to create Images of the human body (or parts thereof for clinical purposes ( Medical procedures seeking to , in real time in countries where this is legal. Using VTC, patients may contact nurses and physicians in emergency or routine situations, physicians and other paramedical professionals can discuss cases across large distances. A nurse is responsible—along with other Health care Professionals —for the treatment safety and recovery of acutely or chronically A physician, medical practitioner or medical doctor who practices Medicine, and is concerned with maintaining or restoring human Health A medical emergency is an Injury or Illness that is acute and poses an immediate risk to a person's life or long term health A paramedic is a medical professional usually a member of the emergency medical service, who primarily provides Pre-hospital advanced medical and Rural areas can use this technology for diagnostic purposes, thus saving lives and making more efficient use of health care money.

Special peripherals such as microscopes fitted with digital cameras, videoendoscopes, medical ultrasound imaging devices, otoscopes, etc. A microscope ( Greek: ( micron) = small + ( skopein) = to look or see is an instrument for viewing objects that are Many compact digital still cameras can record Sound and moving Video as well as still Photograph. Endoscopy means looking inside and typically refers to looking inside the body for medical reasons using an instrument called an endoscope. An Otoscope or auriscope is a medical device which is used to look into the Ears Health care providers use otoscopes to screen for illness during regular , can be used in conjunction with VTC equipment to transmit data about a patient.

Impact on business

Videoconferencing can enable individuals in faraway places to have meetings on short notice. Time and money that used to be spent in traveling can be used to have short meetings. Technology such as VOIP can be used in conjunction with desktop videoconferencing to enable low-cost face-to-face business meetings without leaving the desk, especially for businesses with wide-spread offices. Voice-over-Internet protocol ( VoIP, vɔɪp is a protocol optimized for the transmission of voice through the Internet The technology is also used for telecommuting, in which employees work from home. Telecommuting, e-commuting, e-work, telework, working at home (WAH, or working from home (WFH is a work arrangement in

Videoconferencing is now being introduced to online networking websites, in order to help businesses form profitable relationships quickly and efficiently without leaving their place of work.

Although it already has proven its potential value, research[5] has shown that many employees do not use the videoconference equipment because they are afraid that they will appear to be wasting time or looking for the easiest way if they use videoconferencing to enhance customer and supplier relationships. This anxiety can be avoided if managers use the technology in front of their employees.

Impact on law

Videoconferencing has allowed testimony to be used for individuals who are not able to attend the physical legal settings. In a military investigation in North Carolina, Afghan witnesses have testified using videoconferencing. North Carolina ( is a state located on the Atlantic Seaboard in the southeastern United States

Landmarks

References

  1. ^ Using "Skype" for Desktop Video Conferences 2008, Skype Video-Conference Guide
  2. ^ Jim Van Meggelen 2005, The problem with video conferencing.
  3. ^ Vertegaal, "Explaining Effects of Eye Gaze on Mediated Group Conversations: Amount or Synchronization?" ACM Conference on Computer Supported Cooperative Work, 2002. ).
  4. ^ Computer vision approaches to achieving eye contact appeared in the 1990s, such as Teleconferencing Eye Contact Using a Virtual Camera, ACM CHI 1993. More recently gaze correction systems using only a single camera have been shown, such as. Microsoft's GazeMaster system.
  5. ^ Wolfe, Mark. “Broadband videoconferencing as knowledge management tool,” Journal of Knowledge Management 11, no. 2 (2007)

See also

External links

See also Presence (telepresence Telepresence refers to a set of Technologies which allow a person to feel as if they were present to give the appearance Teleconference is the live exchange and mass articulation of Information among persons and machines remote from one another but linked by a Telecommunications system Mobile VoIP is an extension of mobility to a VoIP Voice over IP network A videophone, also known by the trademarked name Picturephone, is a Telephone which is capable of both audio and Video Duplex transmission The Open Directory Project ( ODP) also known as dmoz (from directory

Dictionary

videoconferencing

-verb

  1. Present participle of videoconference.
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