LINK ===> https://fancli.com/2tkaDl
An implementation of methods for extracting an unweighted unipartite graph (i.e. a backbone) from an unweighted unipartite graph, a weighted unipartite graph, the projection of an unweighted bipartite graph , or the projection of a weighted bipartite graph (Neal, 2022 ).
The GBIF Backbone Taxonomy is a single, synthetic management classification with the goal of covering all names GBIF is dealing with. It's the taxonomic backbone that allows GBIF to integrate name based information from different resources, no matter if these are occurrence datasets, species pages, names from nomenclators or external sources like EOL, Genbank or IUCN. This backbone allows taxonomic search, browse and reporting operations across all those resources in a consistent way and to provide means to crosswalk names from one source to another.
It is updated regulary through an automated process in which the Catalogue of Life acts as a starting point also providing the complete higher classification above families. Additional scientific names only found in other authoritative nomenclatural and taxonomic datasets are then merged into the tree, thus extending the original catalogue and broadening the backbones name coverage. The GBIF Backbone taxonomy also includes identifiers for Operational Taxonomic Units (OTUs) drawn from the barcoding resources iBOL and UNITE.
The Internet backbone may be defined by the principal data routes between large, strategically interconnected computer networks and core routers of the Internet. These data routes are hosted by commercial, government, academic and other high-capacity network centers, as well as the Internet exchange points and network access points, that exchange Internet traffic between the countries, continents, and across the oceans. Internet service providers, often Tier 1 networks, participate in Internet backbone traffic by privately negotiated interconnection agreements, primarily governed by the principle of settlement-free peering.
The Internet, and consequently its backbone networks, do not rely on central control or coordinating facilities, nor do they implement any global network policies. The resilience of the Internet results from its principal architectural features, most notably the idea of placing as few network state and control functions as possible in the network elements and instead relying on the endpoints of communication to handle most of the processing to ensure data integrity, reliability, and authentication. In addition, the high degree of redundancy of today's network links and sophisticated real-time routing protocols provide alternate paths of communications for load balancing and congestion avoidance.
The Internet backbone consists of many networks owned by numerous companies. Optical fiber trunk lines consist of many fiber cables bundled to increase capacity, or bandwidth. Fiber-optic communication remains the medium of choice for Internet backbone providers for several reasons. Fiber-optics allow for fast data speeds and large bandwidth, they suffer relatively little attenuation, allowing them to cover long distances with few repeaters, and they are also immune to crosstalk and other forms of electromagnetic interference which plague electrical transmission. The real-time routing protocols and redundancy built into the backbone is also able to reroute traffic in case of a failure. The data rates of backbone lines have increased over time. In 1998, all of the United States' backbone networks had utilized the slowest data rate of 45 Mbit/s. However, technological improvements allowed for 41 percent of backbones to have data rates of 2,488 Mbit/s or faster by the mid 2000s.
The first packet-switched computer networks, the NPL network and the ARPANET were interconnected in 1973 via University College London. The ARPANET used a backbone of routers called Interface Message Processors. Other packet-switched computer networks proliferated starting in the 1970s, eventually adopting TCP/IP protocols, or being replaced by newer networks. The National Science Foundation created the National Science Foundation Network (NSFNET) in 1986 by funding six networking sites using 56kbit/s interconnecting links, with peering to the ARPANET. In 1987, this new network was upgraded to 1.5Mbit/s T1 links for thirteen sites. These sites included regional networks that in turn connected over 170 other networks. IBM, MCI and Merit upgraded the backbone to 45Mbit/s bandwidth (T3) in 1991. The combination of the ARPANET and NSFNET became known as the Internet. Within a few years, the dominance of the NSFNet backbone led to the decommissioning of the redundant ARPANET infrastructure in 1990.
In the early days of the Internet, backbone providers exchanged their traffic at government-sponsored network access points (NAPs), until the government privatized the Internet, and transferred the NAPs to commercial providers.
Because of the overlap and synergy between long-distance telephone networks and backbone networks, the largest long-distance voice carriers such as AT&T Inc., MCI (acquired in 2006 by Verizon), Sprint, and Lumen also own some of the largest Internet backbone networks. These backbone providers sell their services to Internet service providers (ISPs).
Antitrust authorities have acted to ensure that no provider grows large enough to dominate the backbone market. In the United States, the Federal Communications Commission has decided not to monitor the competitive aspects of the Internet backbone interconnection relationships as long as the market continues to function well.
Europe is a major contributor to the growth of the international backbone as well as a contributor to the growth of Internet bandwidth. In 2003, Europe was credited with 82 percent of the world's international cross-border bandwidth. The company Level 3 Communications began to launch a line of dedicated Internet access and virtual private network services in 2011, giving large companies direct access to the tier 3 backbone. Connecting companies directly to the backbone will provide enterprises faster Internet service which meets a large market demand.
Certain countries around the Caucasus have very simple backbone networks; for example, in 2011, a 70-year-old woman in Georgia pierced a fiber backbone line with a shovel and left the neighboring country of Armenia without Internet access for 12 hours. The country has since made major developments to the fiber backbone infrastructure, but progress is slow due to lack of government funding.
Japan's Internet backbone needs to be very efficient due to high demand for the Internet and technology in general. Japan had over 86 million Internet users in 2009, and was projected to climb to nearly 91 million Internet users by 2015. Since Japan has a demand for fiber to the home, Japan is looking into tapping a fiber-optic backbone line of Nippon Telegraph and Telephone (NTT), a domestic backbone carrier, in order to deliver this service at cheaper prices.
In some instances, the companies that own certain sections of the Internet backbone's physical infrastructure depend on competition in order to keep the Internet market profitable. This can be seen most prominently in China. Since China Telecom and China Unicom have acted as the sole Internet service providers to China for some time, smaller companies cannot compete with them in negotiating the interconnection settlement prices that keep the Internet market profitable in China. This imposition of discriminatory pricing by the large companies then results in market inefficiencies and stagnation, and ultimately affects the efficiency of the Internet backbone networks that service the nation.
In this series of posts, we share our experience to help funders see backbone support as a strategy to advance collective impact initiatives. We hope to build a common language and understanding for the role and value of backbone organizations so that all partners in a collective impact effort can articulate the need for and the importance of this vital element, and ensure the overall success of an initiative. 59ce067264