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Open Spectrum
Open spectrum (also known as free spectrum) is a movement to get the Federal Communications Commission to provide more unlicensed radio-frequency spectrum that is available for use by all. Proponents of the "commons model" of open spectrum advocate a future where all the spectrum is shared, and in which people use Internet protocols to communicate with each other, and smart devices, which would find the most effective energy level, frequency, and mechanism. Previous government-imposed limits on who can have stations and who cannot would be removed, and everyone would be given equal opportunity to use the airwaves for their own radio station, television station, or even broadcast their own website. A notable advocate for Open Spectrum is Lawrence Lessig. National governments currently allocate bands of spectrum (sometimes based on guidelines from the ITU) for use by anyone so long as they respect certain technical limits, most notably, a limit on total transmission power. Unlicensed ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Federal Communications Commission
The Federal Communications Commission (FCC) is an independent agency of the United States government that regulates communications by radio, television, wire, internet, wi-fi, satellite, and cable across the United States. The FCC maintains jurisdiction over the areas of broadband access, fair competition, radio frequency use, media responsibility, public safety, and homeland security. The FCC was established pursuant to the Communications Act of 1934 to replace the radio regulation functions of the previous Federal Radio Commission. The FCC took over wire communication regulation from the Interstate Commerce Commission. The FCC's mandated jurisdiction covers the 50 states, the District of Columbia, and the territories of the United States. The FCC also provides varied degrees of cooperation, oversight, and leadership for similar communications bodies in other countries in North America. The FCC is funded entirely by regulatory fees. It has an estimated fiscal-2022 budg ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Mesh Networks
A mesh network is a local area network topology in which the infrastructure nodes (i.e. bridges, switches, and other infrastructure devices) connect directly, dynamically and non-hierarchically to as many other nodes as possible and cooperate with one another to efficiently route data to and from clients. This lack of dependency on one node allows for every node to participate in the relay of information. Mesh networks dynamically self-organize and self-configure, which can reduce installation overhead. The ability to self-configure enables dynamic distribution of workloads, particularly in the event a few nodes should fail. This in turn contributes to fault-tolerance and reduced maintenance costs. Mesh topology may be contrasted with conventional star/tree local network topologies in which the bridges/switches are directly linked to only a small subset of other bridges/switches, and the links between these infrastructure neighbours are hierarchical. While star-and-tree topologi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Wireless Networking
A wireless network is a computer network that uses wireless data connections between network nodes. Wireless networking allows homes, telecommunications networks, and business installations to avoid the costly process of introducing cables into a building, or as a connection between various equipment locations. Admin telecommunications networks are generally implemented and administered using radio communication. This implementation takes place at the physical level (layer) of the OSI model network structure. Examples of wireless networks include cell phone networks, wireless local area networks (WLANs), wireless sensor networks, satellite communication networks, and terrestrial microwave networks. History Wireless networks The first professional wireless network was developed under the brand ALOHAnet in 1969 at the University of Hawaii and became operational in June 1971. The first commercial wireless network was the WaveLAN product family, developed by NCR in 198 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Spectrum Commons Theory
The Spectrum Commons theory states that the telecommunication radio spectrum should be directly managed by its users rather than regulated by governmental or private institutions. Spectrum management is the process of regulating the use of radio frequencies to promote efficient use and gain a net social benefit. The theory of Spectrum Commons argues that there are new methods and strategies that will allow almost complete open access to this currently regulated commons with unlimited number of persons to share it without causing interference. This would eliminate the need for both a centralized, governmental management of the spectrum and the allocation of specific portions of the spectrum to private actors. The Spectrum debate The Spectrum Commons theory was developed to open up the spectrum to everyone. Users can share a spectrum as a commons without prior authorization from higher governance or regime. Proponents of spectrum commons theory believe government allocation of the sp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Pirate Radio
Pirate radio is a radio station that broadcasts without a valid license, whether an invalid license or no license at all. In some cases, radio stations are considered legal where the signal is transmitted, but illegal where the signals are received—especially when the signals cross a national boundary. In other cases, a broadcast may be considered "pirate" due to the nature of its content, its transmission format (especially a failure to transmit a station identification according to regulations), or the transmit power (wattage) of the station, even if the transmission is not technically illegal (such as an amateur radio transmission). Pirate radio is sometimes called bootleg radio (a term especially associated with two-way radio), clandestine radio (associated with heavily politically motivated operations) or free radio. History Radio "piracy" began with the advent of regulation of the airwaves at the dawn of the age of radio. Initially, radio, or wireless as it wa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Media Democracy
Media democracy is a democratic approach to media studies that advocates for the reform of mass media to strengthen public service broadcasting and develop participation in alternative media and citizen journalism in order to create a mass media system that informs and empowers all members of society and enhances democratic values. Media democracy is both a theory and a social movement. It is against concentration in the ownership of media, and it champions diversity of voices and perspectives within the news system. Definition Media democracy focuses on the empowerment of individual citizens and on the promotion of democratic ideals through the spread of information. Additionally, the approach argues that the media system itself should be democratic in its own construction, shying away from private ownership or intense regulations. Media democracy entails that media should be used to promote democracy and that media itself should be democratic. For example, it views media owners ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Media Consolidation
Media may refer to: Communication * Means of communication, tools and channels used to deliver information or data ** Advertising media, various media, content, buying and placement for advertising ** Interactive media, media that is interactive ** Media adequacy, specific aspects important for a successful transfer of information ** MEDIA sub-programme of Creative Europe, a European Union initiative to support the European audiovisual sector ** New media, the combination of traditional media and information and communications technology ** Print media, communications delivered via paper or canvas ** Recording medium, devices used to store information * Mass media, the institutions and methods of reaching a large audience ** Broadcast media, communications delivered over mass electronic communication networks ** News media, mass media focused on communicating news ** Published media, any media made available to the public * Electronic media, communications deliver ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Universe
The universe is all of space and time and their contents. It comprises all of existence, any fundamental interaction, physical process and physical constant, and therefore all forms of matter and energy, and the structures they form, from sub-atomic particles to entire Galaxy filament, galactic filaments. Since the early 20th century, the field of cosmology establishes that space and time emerged together at the Big Bang ago and that the Expansion of the universe, universe has been expanding since then. The observable universe, portion of the universe that can be seen by humans is approximately 93 billion light-years in diameter at present, but the total size of the universe is not known. Some of the earliest Timeline of cosmological theories, cosmological models of the universe were developed by ancient Greek philosophy, ancient Greek and Indian philosophy, Indian philosophers and were geocentric model, geocentric, placing Earth at the center. Over the centuries, more prec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Radio Galaxy
A radio galaxy is a galaxy with giant regions of radio emission extending well beyond its visible structure. These energetic radio lobes are powered by jets from its active galactic nucleus. They have luminosities up to 1039 W at radio wavelengths between 10 MHz and 100 GHz. The radio emission is due to the synchrotron process. The observed structure in radio emission is determined by the interaction between twin jets and the external medium, modified by the effects of relativistic beaming. The host galaxies are almost exclusively large elliptical galaxies. ''Radio-loud'' active galaxies can be detected at large distances, making them valuable tools for observational cosmology. Recently, much work has been done on the effects of these objects on the intergalactic medium, particularly in galaxy groups and clusters. The term "radio galaxy" is often used to refer to the entire jet system, rather than solely to its host galaxy. Some scientists consider the term " ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Milky Way
The Milky Way or Milky Way Galaxy is the galaxy that includes the Solar System, with the name describing the #Appearance, galaxy's appearance from Earth: a hazy band of light seen in the night sky formed from stars in other arms of the galaxy, which are so far away that they cannot be individually distinguished by the naked eye. The Milky Way is a barred spiral galaxy with a Galaxy#Isophotal diameter, D25 isophotal diameter estimated at , but only about 1,000 light-years thick at the spiral arms (more at the bulge). Recent simulations suggest that a dark matter area, also containing some visible stars, may extend up to a diameter of almost 2 million light-years (613 kpc). The Milky Way has several List of Milky Way's satellite galaxies, satellite galaxies and is part of the Local Group of galaxies, forming part of the Virgo Supercluster which is itself a component of the Laniakea Supercluster. It is estimated to contain 100–400 billion stars and at least that number of pla ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Pulsar
A pulsar (''pulsating star, on the model of quasar'') is a highly magnetized rotating neutron star that emits beams of electromagnetic radiation out of its Poles of astronomical bodies#Magnetic poles, magnetic poles. This radiation can be observed only when a beam of emission is pointing toward Earth (similar to the way a lighthouse can be seen only when the light is pointed in the direction of an observer), and is responsible for the pulsed appearance of emission. Neutron stars are very density, dense and have short, regular rotational Period (physics), periods. This produces a very precise interval between pulses that ranges from milliseconds to seconds for an individual pulsar. Pulsars are one of the candidates for the source of ultra-high-energy cosmic rays (see also centrifugal mechanism of acceleration). Pulsars’ highly regular pulses make them very useful tools for astronomers. For example, observations of a pulsar in a PSR B1913+16, binary neutron star system were use ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Radio Telescope
A radio telescope is a specialized antenna (radio), antenna and radio receiver used to detect radio waves from astronomical radio sources in the sky. Radio telescopes are the main observing instrument used in radio astronomy, which studies the radio frequency portion of the electromagnetic spectrum, just as optical telescopes are used to make observations in the visible light, visible portion of the spectrum in traditional optical astronomy. Unlike optical telescopes, radio telescopes can be used in the daytime as well as at night. Since astronomical radio sources such as planets, stars, nebulas and galaxy, galaxies are very far away, the radio waves coming from them are extremely weak, so radio telescopes require very large antennas to collect enough radio energy to study them, and extremely sensitive receiving equipment. Radio telescopes are typically large Parabolic antenna, parabolic ("dish") antennas similar to those employed in tracking and communicating with satellites an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
