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They are often the response on market failures, i.e., circumstances that prevent perfect competition and achieving an optimal equilibrium in the market. In the context of markets, "perfect competition" means: all participants have complete information, there are no entry or exit barriers to the market, there are no transaction costs or subsidies affecting the market, all firms have constant returns to scale, and all market participants are independent rational actors.Many different kinds of events, actions, policies, or beliefs can bring about a market distortion. For example: almost all types of taxes and subsidies, but especially excise or ad valorem taxes/subsidies, asymmetric information or uncertainty among market participants, any policy or action that restricts information critical to the market, monopoly, oligopoly, or monopsony powers of market participants, criminal coercion or subversion of legal contracts, illiquidity of the market (lack of buyers, sellers, product, or money), collusion among market participants, mass non-rational behavior by market participants, price supports or subsidies, failure of government to provide a stable currency, failure of government to enforce the Rule of Law, failure of government to protect property rights, failure of government to regulate non-competitive market behavior, stifling or corrupt government regulation. nonconvex consumer preference sets market externalities natural factors that impede competition between firms, such as occurs in land markets | https://en.wikipedia.org/wiki/Market_distortion |
In neoclassical economics, economic rent is any payment (in the context of a market transaction) to the owner of a factor of production in excess of the cost needed to bring that factor into production. In classical economics, economic rent is any payment made (including imputed value) or benefit received for non-produced inputs such as location (land) and for assets formed by creating official privilege over natural opportunities (e.g., patents). In the moral economy of neoclassical economics, economic rent includes income gained by labor or state beneficiaries of other "contrived" (assuming the market is natural, and does not come about by state and social contrivance) exclusivity, such as labor guilds and unofficial corruption. | https://en.wikipedia.org/wiki/Economic_rent |
In neoclassical economics, market failure is a situation in which the allocation of goods and services by a free market is not Pareto efficient, often leading to a net loss of economic value. Market failures can be viewed as scenarios where individuals' pursuit of pure self-interest leads to results that are not efficient – that can be improved upon from the societal point of view. The first known use of the term by economists was in 1958, but the concept has been traced back to the Victorian philosopher Henry Sidgwick. Market failures are often associated with public goods, time-inconsistent preferences, information asymmetries, non-competitive markets, principal–agent problems, or externalities.The existence of a market failure is often the reason that self-regulatory organizations, governments or supra-national institutions intervene in a particular market. | https://en.wikipedia.org/wiki/Market_failures |
Economists, especially microeconomists, are often concerned with the causes of market failure and possible means of correction. Such analysis plays an important role in many types of public policy decisions and studies. However, government policy interventions, such as taxes, subsidies, wage and price controls, and regulations, may also lead to an inefficient allocation of resources, sometimes called government failure. | https://en.wikipedia.org/wiki/Market_failures |
Most mainstream economists believe that there are circumstances (like building codes or endangered species) in which it is possible for government or other organizations to improve the inefficient market outcome. Several heterodox schools of thought disagree with this as a matter of ideology.An ecological market failure exists when human activity in a market economy is exhausting critical non-renewable resources, disrupting fragile ecosystems, or overloading biospheric waste absorption capacities. In none of these cases does the criterion of Pareto efficiency obtain. It is critical to create checks on human activities that cause societal negative externalities. | https://en.wikipedia.org/wiki/Market_failures |
In neoclassical economics, the supply and demand of each factor of production interact in factor markets to determine equilibrium output, income, and the income distribution. Factor demand in turn incorporates the marginal-productivity relationship of that factor in the output market. Analysis applies to not only capital and land but the distribution of income in labor markets.The neoclassical growth model provides an account of how the distribution of income between capital and labor is determined in competitive markets at the macroeconomic level over time with technological change and changes in the size of the capital stock and labor force. More recent developments of the distinction between human capital and physical capital and between social capital and personal capital have deepened analysis of distribution. | https://en.wikipedia.org/wiki/Land_distribution |
In neoclassical economics, the value of an object or service is often seen as nothing but the price it would bring in an open and competitive market. This is determined primarily by the demand for the object relative to supply in a perfectly competitive market. Many neoclassical economic theories equate the value of a commodity with its price, whether the market is competitive or not. As such, everything is seen as a commodity and if there is no market to set a price then there is no economic value. | https://en.wikipedia.org/wiki/Monetary_value |
In classical economics, the value of an object or condition is the amount of discomfort/labor saved through the consumption or use of an object or condition (Labor Theory of Value). Though exchange value is recognized, economic value is not, in theory, dependent on the existence of a market and price and value are not seen as equal. This is complicated, however, by the efforts of classical economists to connect price and labor value. | https://en.wikipedia.org/wiki/Monetary_value |
Karl Marx, for one, saw exchange value as the "form of appearance" (This interpretation of Marx is along the lines of the Marxist thinker Michael Heinrich) of value, in his critique of political economy which implies that, although value is separate from exchange value, it is meaningless without the act of exchange. In this tradition, Steve Keen makes the claim that "value" refers to "the innate worth of a commodity, which determines the normal ('equilibrium') ratio at which two commodities exchange." To Keen and the tradition of David Ricardo, this corresponds to the classical concept of long-run cost-determined prices, what Adam Smith called "natural prices" and Marx called "prices of production". | https://en.wikipedia.org/wiki/Monetary_value |
It is part of a cost-of-production theory of value and price. Ricardo, but not Keen, used a "labor theory of price" in which a commodity's "innate worth" was the amount of labor needed to produce it. "The value of a thing in any given time and place", according to Henry George, "is the largest amount of exertion that anyone will render in exchange for it. | https://en.wikipedia.org/wiki/Monetary_value |
But as men always seek to gratify their desires with the least exertion this is the lowest amount for which a similar thing can otherwise be obtained. "In another classical tradition, Marx distinguished between the "value in use" (use-value, what a commodity provides to its buyer), labor cost which he calls "value" (the socially-necessary labour time it embodies), and "exchange value" (how much labor-time the sale of the commodity can claim, Smith's "labor commanded" value). By most interpretations of his labor theory of value, Marx, like Ricardo, developed a "labor theory of price" where the point of analyzing value was to allow the calculation of relative prices. | https://en.wikipedia.org/wiki/Monetary_value |
Others see values as part of his sociopolitical interpretation and critique of capitalism and other societies, and deny that it was intended to serve as a category of economics. According to a third interpretation, Marx aimed for a theory of the dynamics of price formation but did not complete it. In 1860, John Ruskin published a critique of the economic concept of value from a moral point of view. | https://en.wikipedia.org/wiki/Monetary_value |
He entitled the volume Unto This Last, and his central point was this: "It is impossible to conclude, of any given mass of acquired wealth, merely by the fact of its existence, whether it signifies good or evil to the nation in the midst of which it exists. Its real value depends on the moral sign attached to it, just as strictly as that of a mathematical quantity depends on the algebraic sign attached to it. Any given accumulation of commercial wealth may be indicative, on the one hand, of faithful industries, progressive energies, and productive ingenuities: or, on the other, it may be indicative of mortal luxury, merciless tyranny, ruinous chicanery." | https://en.wikipedia.org/wiki/Monetary_value |
Gandhi was greatly inspired by Ruskin's book and published a paraphrase of it in 1908.Economists such as Ludwig von Mises asserted that "value" is a subjective judgment. Prices can only be determined by taking these subjective judgments into account, and that this is done through the price mechanism in the market. | https://en.wikipedia.org/wiki/Monetary_value |
Thus, it was false to say that the economic value of a good was equal to what it cost to produce or to its current replacement cost. Silvio Gesell denied value theory in economics. He thought that value theory is useless and prevents economics from becoming science and that a currency administration guided by value theory is doomed to sterility and inactivity. | https://en.wikipedia.org/wiki/Monetary_value |
In neoclassical terms, a commodity is a good or service that can be traded or exchanged in the marketplace for another commodity or money. Commodification is routed in Marxist political theory and entails the creation of an economic good that previously was not prescribed an economic value. This takes place through the application of market mechanisms with the intended result being a standardized class of goods or services. | https://en.wikipedia.org/wiki/Commodification_of_water |
Once commodified an economic good can be bought or sold at a price determined by market exchange, and as such market values replace social values previously attached to the good. It is this transformation from a public good to an economic good that neoliberals claim leads to better management and allocation of a resource, such as water. In accordance with welfare economics, this view infers the more efficiently managed a resource is the higher a society's welfare. This neoliberal sentiment of water as an economic good not unlike any other is visible in a quote from The Economist: "Only by accepting water as a tradable commodity will sensible decisions be possible" (The Economist, 1992). | https://en.wikipedia.org/wiki/Commodification_of_water |
In neon glow lamps, the luminous region of the gas is a thin, "negative glow" region immediately adjacent to a negatively charged electrode (or "cathode"); the positively charged electrode ("anode") is quite close to the cathode. These features distinguish glow lamps from the much longer and brighter "positive column" luminous regions in neon tube lighting. The energy dissipation in the lamps when they are glowing is very low (about 0.1 W), hence the distinguishing term cold-cathode lighting. Some of the applications of neon lamps include: Pilot lamps that indicate the presence of electrical power in an appliance or instrument (e.g. an electric coffee pot or power supply). | https://en.wikipedia.org/wiki/Neon_tubes |
Decorative (or "figural") lamps in which the cathode is shaped as a flower, animal, etc.. The figures inside these lamps were typically painted with phosphorescent paints to achieve a variety of colors. Active electronic circuits such as electronic oscillators, timers, memory elements, etc.. Intricate electronic displays such as the Nixie tube (see photograph).The small size of the negative glow region of a neon lamp, and the flexible electronic properties that were exploited in electronic circuits, led to the adoption of this technology for the earliest plasma panel displays. The first monochrome dot-matrix plasma panel displays were developed in 1964 at the University of Illinois for the PLATO educational computing system. | https://en.wikipedia.org/wiki/Neon_tubes |
They had the characteristic color of the neon lamp; their inventors, Donald L. Bitzer, H. Gene Slottow, and Robert H. Wilson, had achieved a working computer display that remembered its own state, and did not require constant refreshing from the central computer system. The relationship between these early monochrome displays and contemporary, color plasma displays and televisions was described by Larry F. Weber in 2006, "All plasma TVs on the market today have the same features that were demonstrated in the first plasma display which was a device with only a single cell. | https://en.wikipedia.org/wiki/Neon_tubes |
These features include alternating sustain voltage, dielectric layer, wall charge, and a neon-based gas mixture." As in colored neon lamps, plasma displays use a gas mixture that emits ultraviolet light. Each pixel has a phosphor that emits one of the display's base colors. | https://en.wikipedia.org/wiki/Neon_tubes |
In neonatal in vivo model of brain ischemia/reperfusion, tissue injury can be alleviated by the administration of FMN precursor, riboflavin that prevents inactivation of mitochondrial complex I. | https://en.wikipedia.org/wiki/Ischemia-reperfusion_injury |
In neonatal life, gonadal steroids influence the development of the neuroendocrine hypothalamus. For instance, they determine the ability of females to exhibit a normal reproductive cycle, and of males and females to display appropriate reproductive behaviors in adult life. If a female rat is injected once with testosterone in the first few days of postnatal life (during the "critical period" of sex-steroid influence), the hypothalamus is irreversibly masculinized; the adult rat will be incapable of generating an LH surge in response to estrogen (a characteristic of females), but will be capable of exhibiting male sexual behaviors (mounting a sexually receptive female). By contrast, a male rat castrated just after birth will be feminized, and the adult will show female sexual behavior in response to estrogen (sexual receptivity, lordosis behavior).In primates, the developmental influence of androgens is less clear, and the consequences are less understood. | https://en.wikipedia.org/wiki/Anterior_hypothalamus |
Within the brain, testosterone is aromatized (to estradiol), which is the principal active hormone for developmental influences. The human testis secretes high levels of testosterone from about week 8 of fetal life until 5–6 months after birth (a similar perinatal surge in testosterone is observed in many species), a process that appears to underlie the male phenotype. Estrogen from the maternal circulation is relatively ineffective, partly because of the high circulating levels of steroid-binding proteins in pregnancy.Sex steroids are not the only important influences upon hypothalamic development; in particular, pre-pubertal stress in early life (of rats) determines the capacity of the adult hypothalamus to respond to an acute stressor. Unlike gonadal steroid receptors, glucocorticoid receptors are very widespread throughout the brain; in the paraventricular nucleus, they mediate negative feedback control of CRF synthesis and secretion, but elsewhere their role is not well understood. | https://en.wikipedia.org/wiki/Anterior_hypothalamus |
In neonatal tetanus, symptoms usually appear from 4 to 14 days after birth, averaging about 7 days. The fatality rate for infants has been estimated as 70% to 100%; death usually occurs by the age of 2 weeks. On the basis of clinical findings, four different forms of tetanus have been described. The time from exposure to symptoms may be up to several months. The neonate is unable to suck and cry, is rigid, and develops spasms. | https://en.wikipedia.org/wiki/Neonatal_tetanus |
In neonates (newborn infants), brown fat makes up about 5% of the body mass and is located on the back, along the upper half of the spine and toward the shoulders. It is of great importance to avoid hypothermia, as lethal cold is a major death risk for premature neonates. Numerous factors make infants more susceptible to cold than adults: A higher ratio of body surface area (proportional to heat loss) to body volume (proportional to heat production) A higher proportional surface area of the head A low amount of musculature and the inability to shiver A lack of thermal insulation, e.g., subcutaneous fat and fine body hair (especially in prematurely born children) An inability to move away from cold areas, air currents or heat-draining materials An inability to use additional ways of keeping warm (e.g., drying their skin, putting on clothing, moving into warmer areas, or performing physical exercise) A nervous system that is not fully developed and does not respond quickly and/or properly to cold (e.g., by contracting blood vessels in and just below the skin: vasoconstriction).Heat production in brown fat provides an infant with an alternative means of heat regulation. | https://en.wikipedia.org/wiki/Brown_fat |
In neonates born at or beyond 35 weeks, neonatal encephalopathy may present itself as the following symptoms: Reduced level of consciousness Seizures (which peak at 48 hours) Difficulty initiating and maintaining respiration Depression of tone and reflexes | https://en.wikipedia.org/wiki/Neonatal_encephalopathy |
In neonates, vaginal discharge sometimes occurs in the first few days after birth. This is due to exposure to estrogen while in utero. Neonatal vaginal discharge may be white or clear with a mucous texture, or it may be bloody from normal transient shedding of the endometrium. | https://en.wikipedia.org/wiki/Vaginal_discharge |
In neonatology, transcranial Doppler can be used for basic assessment of intracerebral structural abnormalities, suspected hemorrhage, ventriculomegaly or hydrocephalus and anoxic insults (periventricular leukomalacia). It can be performed through the soft spots in the skull of a newborn infant (Fontanelle) until these completely close at about 1 year of age by which time they have formed a virtually impenetrable acoustic barrier to ultrasound. The most common site for cranial ultrasound is the anterior fontanelle. The smaller the fontanelle, the more the image is compromised. | https://en.wikipedia.org/wiki/Diagnostic_ultrasound |
In neopaganism there is a wide variety of ritual practice, running the gamut from a very eclectic syncretism to strict polytheistic reconstructionism. Many of these groups make use of altars. Some are constructed merely of rough-hewn or stacked stone, and some are made of fine wood or other finished material. | https://en.wikipedia.org/wiki/Holy_Table |
In nephrology, dialysis adequacy is the measurement of renal dialysis for the purpose of determining dialysis treatment regime and to better understand the pathophysiology of renal dialysis. It is an area of considerable controversy in nephrology.In the US, the dominant way of measuring dialysis adequacy in Kt/V and based on the clearance of urea, though the relevance of this measurement is disputed. | https://en.wikipedia.org/wiki/Dialysis_adequacy |
In nephrology, ultrasonography of the kidneys is essential in the diagnosis and management of kidney-related diseases. The kidneys are easily examined, and most pathological changes are distinguishable with ultrasound. It is an accessible, versatile, relatively economic, and fast aid for decision-making in patients with renal symptoms and for guidance in renal intervention. Using B-mode imaging, assessment of renal anatomy is easily performed, and US is often used as image guidance for renal interventions. Furthermore, novel applications in renal US have been introduced with contrast-enhanced ultrasound (CEUS), elastography and fusion imaging. However, renal US has certain limitations, and other modalities, such as CT (CECT) and MRI, should be considered for supplementary imaging in assessing renal disease. | https://en.wikipedia.org/wiki/Ultrasound_machine |
In net metering the price of the electricity produced is the same as the price supplied to the consumer, and the consumer is billed on the difference between production and consumption. Net metering can usually be done with no changes to standard electricity meters, which accurately measure power in both directions and automatically report the difference, and because it allows homeowners and businesses to generate electricity at a different time from consumption, effectively using the grid as a giant storage battery. With net metering, deficits are billed each month while surpluses are rolled over to the following month. Best practices call for perpetual roll over of kWh credits. Excess credits upon termination of service are either lost or paid for at a rate ranging from wholesale to retail rate or above, as can be excess annual credits. | https://en.wikipedia.org/wiki/Solar_power_plants |
In netball's now-defunct ANZ Championship, which featured five teams each from Australia and New Zealand, each franchise was restricted to a NZ$380,000 salary cap (as of 2013) from which player salaries were paid. Salary amounts varied among players, but each player received a retainer of at least NZ$12,000 per season; high-profile players were expected to earn up to NZ$50,000.Following the 2016 season, Australia's national governing body of Netball Australia broke away from the trans-Tasman championship and launched its own national league, Suncorp Super Netball. The initial team salary cap in the new league was A$675,000, with minimum player salaries of A$27,375. This latter figure was more than double the minimum wage of A$13,250 in the final season of the ANZ Championship. | https://en.wikipedia.org/wiki/Salary_cap |
New Zealand rebranded its now-domestic league as the ANZ Premiership, presumably retaining its prior salary cap provisions. Since then, Super Netball's salary cap has risen modestly. The original team cap of A$675,000 had been structured with a $500,000 cap on playing payments, plus an additional $150,000 for club-related employment, educational, and ambassadorial roles, and the balance for health insurance and technology allowances. For the 2019 season, the minimum player wage (not including the health insurance allowance, set at $1,635 for that season) rises to $30,000, and the team cap on playing payments rises to $515,000. | https://en.wikipedia.org/wiki/Salary_cap |
In netstalking, there are two general methods for finding unusual information: a deli-search and a net-random. Deli-search, or "deliberated search", is a targeted search for objects of interest whose characteristics are already known. This method usually uses the language of search queries and web archives, with which one can view old or deleted versions of these pages. Net-random searches for hidden and unknown information through the process of trial and error. | https://en.wikipedia.org/wiki/Netstalking |
For netstalkers, the second method is considered to be the most popular way to search for information, as it allows network researchers to find undefined hidden resources. Net-randoming is done by either scanning IP address ranges or by using content randomizers, such as PetitTube. Special programs are used for scanning include Advanced IP scanner, Nmap / Zenmap, NESCA, and RouterScan by Stas’m. | https://en.wikipedia.org/wiki/Netstalking |
In network calculus, a flow is modelled as cumulative functions A, where A(t) represents the amount of data (number of bits for example) send by the flow in the interval [0,t). Such functions are non-negative and non-decreasing. The time domain is often the set of non negative reals. A: R + → R + {\displaystyle A:\mathbb {R} ^{+}\rightarrow \mathbb {R} ^{+}} ∀ u , t ∈ R +: u < t ⟹ A ( u ) ≤ A ( t ) {\displaystyle \forall u,t\in \mathbb {R} ^{+}:u | https://en.wikipedia.org/wiki/Network_calculus |
In network computing, frontend can refer to any hardware that optimizes or protects network traffic. It is called application front-end hardware because it is placed on the network's outward-facing frontend or boundary. Network traffic passes through the front-end hardware before entering the network. In processor design, frontend design would be the initial description of the behavior of a circuit in a hardware description language such as Verilog, while backend design would be the process of mapping that behavior to physical transistors on a die. | https://en.wikipedia.org/wiki/Frontend_and_backend |
In network management, fault management is the set of functions that detect, isolate, and correct malfunctions in a telecommunications network, compensate for environmental changes, and include maintaining and examining error logs, accepting and acting on error detection notifications, tracing and identifying faults, carrying out sequences of diagnostics tests, correcting faults, reporting error conditions, and localizing and tracing faults by examining and manipulating database information.When a fault or event occurs, a network component will often send a notification to the network operator using a protocol such as SNMP. An alarm is a persistent indication of a fault that clears only when the triggering condition has been resolved. A current list of problems occurring on the network component is often kept in the form of an active alarm list such as is defined in RFC 3877, the Alarm MIB. A list of cleared faults is also maintained by most network management systems.Fault management systems may use complex filtering systems to assign alarms to severity levels. | https://en.wikipedia.org/wiki/Fault_management |
These can range in severity from debug to emergency, as in the syslog protocol. Alternatively, they could use the ITU X.733 Alarm Reporting Function's perceived severity field. | https://en.wikipedia.org/wiki/Fault_management |
This takes on values of cleared, indeterminate, critical, major, minor or warning. Note that the latest version of the syslog protocol draft under development within the IETF includes a mapping between these two different sets of severities. It is considered good practice to send a notification not only when a problem has occurred, but also when it has been resolved. | https://en.wikipedia.org/wiki/Fault_management |
The latter notification would have a severity of clear. A fault management console allows a network administrator or system operator to monitor events from multiple systems and perform actions based on this information. Ideally, a fault management system should be able to correctly identify events and automatically take action, either launching a program or script to take corrective action, or activating notification software that allows a human to take proper intervention (i.e. send e-mail or SMS text to a mobile phone). Some notification systems also have escalation rules that will notify a chain of individuals based on availability and severity of alarm. | https://en.wikipedia.org/wiki/Fault_management |
In network routing, VCG mechanisms are a family of payment schemes based on the added value concept. The basic idea of a VCG mechanism in network routing is to pay the owner of each link or node (depending on the network model) that is part of the solution, its declared cost plus its added value. In many routing problems, this mechanism is not only strategyproof, but also the minimum among all strategyproof mechanisms. In the case of network flows, unicast or multicast, a minimum cost flow (MCF) in graph G is calculated based on the declared costs dk of each of the links and payment is calculated as follows: Each link (or node) e k {\displaystyle \scriptstyle e_{k}} in the MCF is paid p k = d k + M C F ( G − e k ) − M C F ( G ) {\displaystyle p_{k}=d_{k}+MCF(G-e_{k})-MCF(G)} ,where MCF(G) indicates the cost of the minimum cost flow in graph G and G − ek indicates graph G without the link ek. | https://en.wikipedia.org/wiki/Sealed_second-price_auction |
Links not in the MCF are paid nothing. This routing problem is one of the cases for which VCG is strategyproof and minimum. In 2004, it was shown that the expected VCG overpayment of an Erdős–Rényi random graph with n nodes and edge probability p, G ∈ G ( n , p ) {\displaystyle \scriptstyle G\in G(n,p)} approaches p 2 − p {\displaystyle {\frac {p}{2-p}}} as n, approaches ∞ {\displaystyle \scriptstyle \infty } , for n p = ω ( n log n ) {\displaystyle np=\omega ({\sqrt {n\log n}})} . Prior to this result, it was known that VCG overpayment in G(n, p) is Ω ( 1 n p ) {\displaystyle \Omega \left({\frac {1}{np}}\right)} and O ( 1 ) {\displaystyle O(1)\,} with high probability given n p = ω ( log n ) . {\displaystyle np=\omega (\log n).\,} | https://en.wikipedia.org/wiki/Sealed_second-price_auction |
In network routing, the control plane is the part of the router architecture that is concerned with drawing the network topology, or the information in a routing table that defines what to do with incoming packets. Control plane functions, such as participating in routing protocols, run in the architectural control element. In most cases, the routing table contains a list of destination addresses and the outgoing interface(s) associated with each. | https://en.wikipedia.org/wiki/Control_plane |
Control plane logic also can identify certain packets to be discarded, as well as preferential treatment of certain packets for which a high quality of service is defined by such mechanisms as differentiated services. Depending on the specific router implementation, there may be a separate forwarding information base that is populated by the control plane, but used by the high-speed forwarding plane to look up packets and decide how to handle them. In computing, the control plane is the part of the software that configures and shuts down the data plane. | https://en.wikipedia.org/wiki/Control_plane |
By contrast, the data plane is the part of the software that processes the data requests. The data plane is also sometimes referred to as the forwarding plane. The distinction has proven useful in the networking field where it originated, as it separates the concerns: the data plane is optimized for speed of processing, and for simplicity and regularity. The control plane is optimized for customizability, handling policies, handling exceptional situations, and in general facilitating and simplifying the data plane processing.The conceptual separation of the data plane from the control plane has been done for years. An early example is Unix, where the basic file operations are open, close for the control plane and read write for the data plane. | https://en.wikipedia.org/wiki/Control_plane |
In network science, a biased random walk on a graph is a time path process in which an evolving variable jumps from its current state to one of various potential new states; unlike in a pure random walk, the probabilities of the potential new states are unequal. Biased random walks on a graph provide an approach for the structural analysis of undirected graphs in order to extract their symmetries when the network is too complex or when it is not large enough to be analyzed by statistical methods. The concept of biased random walks on a graph has attracted the attention of many researchers and data companies over the past decade especially in the transportation and social networks. | https://en.wikipedia.org/wiki/Biased_random_walk_on_a_graph |
In network science, a critical point is a value of average degree, which separates random networks that have a giant component from those that do not (i.e. it separates a network in a subcritical regime from one in a supercritical regime). Considering a random network with an average degree ⟨ k ⟩ {\displaystyle \langle k\rangle } the critical point is ⟨ k ⟩ = 1 {\displaystyle \langle k\rangle =1} where the average degree is defined by the fraction of the number of edges ( e {\displaystyle e} ) and nodes ( N {\displaystyle N} ) in the network, that is ⟨ k ⟩ = 2 e N {\displaystyle \langle k\rangle ={\frac {2e}{N}}} . | https://en.wikipedia.org/wiki/Critical_point_(network_science) |
In network science, a gradient network is a directed subnetwork of an undirected "substrate" network where each node has an associated scalar potential and one out-link that points to the node with the smallest (or largest) potential in its neighborhood, defined as the union of itself and its neighbors on the substrate network. | https://en.wikipedia.org/wiki/Gradient_network |
In network science, a hub is a node with a number of links that greatly exceeds the average. Emergence of hubs is a consequence of a scale-free property of networks. : 27 While hubs cannot be observed in a random network, they are expected to emerge in scale-free networks. The uprise of hubs in scale-free networks is associated with power-law distribution. | https://en.wikipedia.org/wiki/Hub_(network_science) |
Hubs have a significant impact on the network topology. Hubs can be found in many real networks, such as the brain or the Internet. A hub is a component of a network with a high-degree node. | https://en.wikipedia.org/wiki/Hub_(network_science) |
Hubs have a significantly larger number of links in comparison with other nodes in the network. The number of links (degrees) for a hub in a scale-free network is much higher than for the biggest node in a random network, keeping the size N of the network and average degree constant. The existence of hubs is the biggest difference between random networks and scale-free networks. In random networks, the degree k is comparable for every node; it is therefore not possible for hubs to emerge. In scale-free networks, a few nodes (hubs) have a high degree k while the other nodes have a small number of links. | https://en.wikipedia.org/wiki/Hub_(network_science) |
In network science, a sparse network has much fewer links than the possible maximum number of links within that network (the opposite is a dense network). The study of sparse networks is a relatively new area primarily stimulated by the study of real networks, such as social and computer networks.The notion of much fewer links is, of course, colloquial and informal. While a threshold for a particular network may be invented, there is no universal threshold that defines what much fewer actually means. As a result, there is no formal sense of sparsity for any finite network, despite widespread agreement that most empirical networks are indeed sparse. There is, however, a formal sense of sparsity in the case of infinite network models, determined by the behavior of the number of edges (M) and/or the average degree (⟨k⟩) as the number of nodes (N) goes to infinity. | https://en.wikipedia.org/wiki/Dense_network |
In network science, ingredient-flavor networks are networks describing the sharing of flavor compounds of culinary ingredients. In the bipartite form, an ingredient-flavor network consist of two different types of nodes: the ingredients used in the recipes and the flavor compounds that contributes to the flavor of each ingredients. The links connecting different types of nodes are undirected, represent certain compound occur in each ingredients. The ingredient-flavor network can also be projected in the ingredient or compound space where nodes are ingredients or compounds, links represents the sharing of the same compounds to different ingredients or the coexistence in the same ingredient of different compounds. | https://en.wikipedia.org/wiki/Ingredient-flavor_network |
In network science, preferential attachment means that nodes of a network tend to connect to those nodes which have more links. If the network is growing and new nodes tend to connect to existing ones with linear probability in the degree of the existing nodes then preferential attachment leads to a scale-free network. If this probability is sub-linear then the network’s degree distribution is stretched exponential and hubs are much smaller than in a scale-free network. If this probability is super-linear then almost all nodes are connected to a few hubs. | https://en.wikipedia.org/wiki/Non-linear_preferential_attachment |
According to Kunegis, Blattner, and Moser several online networks follow a non-linear preferential attachment model. Communication networks and online contact networks are sub-linear while interaction networks are super-linear. The co-author network among scientists also shows the signs of sub-linear preferential attachment. | https://en.wikipedia.org/wiki/Non-linear_preferential_attachment |
In network science, reciprocity is a measure of the likelihood of vertices in a directed network to be mutually linked. Like the clustering coefficient, scale-free degree distribution, or community structure, reciprocity is a quantitative measure used to study complex networks. | https://en.wikipedia.org/wiki/Reciprocity_(network_science) |
In network science, the Matthew effect is used to describe the preferential attachment of earlier nodes in a network, which explains that these nodes tend to attract more links early on. "Because of preferential attachment, a node that acquires more connections than another one will increase its connectivity at a higher rate, and thus an initial difference in the connectivity between two nodes will increase further as the network grows, while the degree of individual nodes will grow proportional with the square root of time." The Matthew Effect therefore explains the growth of some nodes in vast networks such as the Internet. | https://en.wikipedia.org/wiki/Matthew_effect_(sociology) |
In network science, the activity-driven model is a temporal network model in which each node has a randomly-assigned "activity potential", which governs how it links to other nodes over time. Each node j {\displaystyle j} (out of N {\displaystyle N} total) has its activity potential x i {\displaystyle x_{i}} drawn from a given distribution F ( x ) {\displaystyle F(x)} . A sequence of timesteps unfolds, and in each timestep each node j {\displaystyle j} forms ties to m {\displaystyle m} random other nodes at rate a i = η x i {\displaystyle a_{i}=\eta x_{i}} (more precisely, it does so with probability a i Δ t {\displaystyle a_{i}\,\Delta t} per timestep). All links are then deleted after each timestep. | https://en.wikipedia.org/wiki/Activity-driven_model |
Properties of time-aggregated network snapshots are able to be studied in terms of F ( x ) {\displaystyle F(x)} . For example, since each node j {\displaystyle j} after T {\displaystyle T} timesteps will have on average m η x i T {\displaystyle m\eta x_{i}T} outgoing links, the degree distribution after T {\displaystyle T} timesteps in the time-aggregated network will be related to the activity-potential distribution by P T ( k ) ∝ F ( k m η T ) . {\displaystyle P_{T}(k)\propto F\left({\frac {k}{m\eta T}}\right).} Spreading behavior according to the SIS epidemic model was investigated on activity-driven networks, and the following condition was derived for large-scale outbreaks to be possible: β λ > 2 ⟨ a ⟩ ⟨ a ⟩ + ⟨ a 2 ⟩ , {\displaystyle {\frac {\beta }{\lambda }}>{\frac {2\langle a\rangle }{\langle a\rangle +{\sqrt {\langle a^{2}\rangle }}}},} where β {\displaystyle \beta } is the per-contact transmission probability, λ {\displaystyle \lambda } is the per-timestep recovery probability, and ( ⟨ a ⟩ {\displaystyle \langle a\rangle } , ⟨ a 2 ⟩ {\displaystyle \langle a^{2}\rangle } ) are the first and second moments of the random activity-rate a j {\displaystyle a_{j}} . | https://en.wikipedia.org/wiki/Activity-driven_model |
In network science, the configuration model is a method for generating random networks from a given degree sequence. It is widely used as a reference model for real-life social networks, because it allows the modeler to incorporate arbitrary degree distributions. | https://en.wikipedia.org/wiki/Configuration_model |
In network science, the efficiency of a network is a measure of how efficiently it exchanges information and it is also called communication efficiency. The underlying idea (and main assumption) is that the more distant two nodes are in the network, the less efficient their communication will be. The concept of efficiency can be applied to both local and global scales in a network. | https://en.wikipedia.org/wiki/Efficiency_(network_science) |
On a global scale, efficiency quantifies the exchange of information across the whole network where information is concurrently exchanged. The local efficiency quantifies a network's resistance to failure on a small scale. That is the local efficiency of a node i {\displaystyle i} characterizes how well information is exchanged by its neighbors when it is removed. | https://en.wikipedia.org/wiki/Efficiency_(network_science) |
In network science, the strength notated as si of a node i is defined as si = Σjwij, where wij is the weight of the link between i and j. In order to apply the disparity filter algorithm without overlooking nodes with low strength, a normalized weight pij is defined as pij = wij/si. In the null model, the normalized weights of a certain node with degree k is generated like this: k − 1 pins are randomly assigned between the interval 0 and 1. The interval is then divided into k subintervals. The length of the subinterval represents the normalized weight of each link in the null model. Consecutively, and based on the null model, we can derive that the normalized weight distribution of a node with degree k follows ρ ( x ) d x = ( k − 1 ) ( 1 − x ) k − 2 d x {\displaystyle \rho (x)\,dx=(k-1)(1-x)^{k-2}\,dx} . | https://en.wikipedia.org/wiki/Disparity_filter_algorithm_of_weighted_network |
In network security a screened subnet refers to the use of one or more logical screening routers as a firewall to define three separate subnets: an external router (sometimes called an access router), that separates the external network from a perimeter network, and an internal router (sometimes called a choke router) that separates the perimeter network from the internal network. The perimeter network, also called a border network or demilitarized zone (DMZ), is intended for hosting servers (sometimes called bastion hosts) that are accessible from or have access to both the internal and external networks. The purpose of a screened subnet or DMZ is to establish a network with heightened security that is situated between an external and presumed hostile network, such as the Internet or an extranet, and an internal network. A screened subnet is an essential concept for e-commerce or any entity that has a presence in the World Wide Web or is using electronic payment systems or other network services because of the prevalence of hackers, advanced persistent threats, computer worms, botnets, and other threats to networked information systems. | https://en.wikipedia.org/wiki/Screened_subnet |
In network security, evasion is bypassing an information security defense in order to deliver an exploit, attack, or other form of malware to a target network or system, without detection. Evasions are typically used to counter network-based intrusion detection and prevention systems (IPS, IDS) but can also be used to by-pass firewalls and defeat malware analysis. A further target of evasions can be to crash a network security defense, rendering it in-effective to subsequent targeted attacks. | https://en.wikipedia.org/wiki/Evasion_(network_security) |
In network theory, a giant component is a connected component of a given random graph that contains a significant fraction of the entire graph's vertices. More precisely, in graphs drawn randomly from a probability distribution over arbitrarily large graphs, a giant component is a connected component whose fraction of the overall number of vertices is bounded away from zero. In sufficiently dense graphs distributed according to the Erdős–Rényi model, a giant component exists with high probability. | https://en.wikipedia.org/wiki/Giant_component |
In network theory, collective classification is the simultaneous prediction of the labels for multiple objects, where each label is predicted using information about the object's observed features, the observed features and labels of its neighbors, and the unobserved labels of its neighbors. Collective classification problems are defined in terms of networks of random variables, where the network structure determines the relationship between the random variables. Inference is performed on multiple random variables simultaneously, typically by propagating information between nodes in the network to perform approximate inference. Approaches that use collective classification can make use of relational information when performing inference. Examples of collective classification include predicting attributes (ex. gender, age, political affiliation) of individuals in a social network, classifying webpages in the World Wide Web, and inferring the research area of a paper in a scientific publication dataset. | https://en.wikipedia.org/wiki/Collective_classification |
In network theory, link analysis is a data-analysis technique used to evaluate relationships (Tap link) between nodes. Relationships may be identified among various types of nodes (100k), including organizations, people and transactions. Link analysis has been used for investigation of criminal activity (fraud , counterterrorism, and intelligence), computer security analysis, search engine optimization, market research, medical research, and art. | https://en.wikipedia.org/wiki/Link_analysis |
In network theory, link prediction is the problem of predicting the existence of a link between two entities in a network. Examples of link prediction include predicting friendship links among users in a social network, predicting co-authorship links in a citation network, and predicting interactions between genes and proteins in a biological network. Link prediction can also have a temporal aspect, where, given a snapshot of the set of links at time t {\displaystyle t} , the goal is to predict the links at time t + 1 {\displaystyle t+1} . Link prediction is widely applicable. | https://en.wikipedia.org/wiki/Link_prediction |
In e-commerce, link prediction is often a subtask for recommending items to users. In the curation of citation databases, it can be used for record deduplication. In bioinformatics, it has been used to predict protein-protein interactions (PPI). It is also used to identify hidden groups of terrorists and criminals in security related applications. | https://en.wikipedia.org/wiki/Link_prediction |
In network theory, multidimensional networks, a special type of multilayer network, are networks with multiple kinds of relations. Increasingly sophisticated attempts to model real-world systems as multidimensional networks have yielded valuable insight in the fields of social network analysis, economics, urban and international transport, ecology, psychology, medicine, biology, commerce, climatology, physics, computational neuroscience, operations management, and finance. | https://en.wikipedia.org/wiki/Multidimensional_network |
In network theory, small-world routing refers to routing methods for small-world networks. Networks of this type are peculiar in that relatively short paths exist between any two nodes. Determining these paths, however, can be a difficult problem from the perspective of an individual routing node in the network if no further information is known about the network as a whole. | https://en.wikipedia.org/wiki/Small-world_routing |
In network theory, the Braunstein–Ghosh–Severini entropy (BGS entropy) of a network is the von Neumann entropy of a density matrix given by a normalized Laplacian matrix of the network. This definition of entropy does not have a clear thermodynamical interpretation. The BGS entropy has been used in the context of quantum gravity. == Notes and references == | https://en.wikipedia.org/wiki/Braunstein–Ghosh–Severini_entropy |
In network theory, the Wiener connector is a means of maximizing efficiency in connecting specified "query vertices" in a network. Given a connected, undirected graph and a set of query vertices in a graph, the minimum Wiener connector is an induced subgraph that connects the query vertices and minimizes the sum of shortest path distances among all pairs of vertices in the subgraph. In combinatorial optimization, the minimum Wiener connector problem is the problem of finding the minimum Wiener connector. It can be thought of as a version of the classic Steiner tree problem (one of Karp's 21 NP-complete problems), where instead of minimizing the size of the tree, the objective is to minimize the distances in the subgraph.The minimum Wiener connector was first presented by Ruchansky et al. in 2015.The minimum Wiener connector has applications in many domains where there is a graph structure and an interest in learning about connections between sets of individuals. | https://en.wikipedia.org/wiki/Wiener_connector |
For example, given a set of patients infected with a viral disease, which other patients should be checked to find the culprit? Or given a set of proteins of interest, which other proteins participate in pathways with them? The Wiener connector was named in honor of chemist Harry Wiener who first introduced the Wiener Index. | https://en.wikipedia.org/wiki/Wiener_connector |
In network topology, a cable modem is a network bridge that conforms to IEEE 802.1D for Ethernet networking (with some modifications). The cable modem bridges Ethernet frames between a customer LAN and the coax network. Technically, it is a modem because it must modulate data to transmit it over the cable network, and it must demodulate data from the cable network to receive it. | https://en.wikipedia.org/wiki/Cable_modems |
With respect to the OSI model of network design, a cable modem is both physical layer (layer 1) device and a data link layer (layer 2) forwarder. As an IP addressable network node, cable modems support functionality at other layers. Layer 1 is implemented in the Ethernet PHY on its LAN interface, and a DOCSIS defined cable-specific PHY on its HFC cable interface. | https://en.wikipedia.org/wiki/Cable_modems |
The term cable modem refers to this cable-specific PHY. The Network Layer (Layer 3) is implemented as an IP host in that it has its own IP address used by the network operator to maintain the device. In the transport layer (layer 4) the cable modem supports UDP in association with its own IP address, and it supports filtering based on TCP and UDP port numbers to, for example, block forwarding of NetBIOS traffic out of the customer's LAN. | https://en.wikipedia.org/wiki/Cable_modems |
In the Application Layer (Layer 7), the cable modem supports certain protocols that are used for management and maintenance, notably Dynamic Host Configuration Protocol (DHCP), SNMP, and TFTP. Some cable modems may incorporate a router and a DHCP server to provide the LAN with IP network addressing. From a data forwarding and network topology perspective, this router functionality is typically kept distinct from the cable modem functionality (at least logically) even though the two may share a single enclosure and appear as one unit, sometimes called a residential gateway. So, the cable modem function will have its own IP address and MAC address as will the router. | https://en.wikipedia.org/wiki/Cable_modems |
In networked systems where competitive decision making takes place, game theory is often used to model system dynamics, and convergence towards equilibria can be considered as a driver of topological evolution. For example, Kasthurirathna and Piraveenan have shown that when individuals in a system display varying levels of rationality, improving the overall system rationality might be an evolutionary reason for the emergence of scale-free networks. They demonstrated this by applying evolutionary pressure on an initially random network which simulates a range of classic games, so that the network converges towards Nash equilibria while being allowed to re-wire. The networks become increasingly scale-free during this process. | https://en.wikipedia.org/wiki/Evolving_networks |
In networking and in graph theory, capillary routing, for a given network, is a multi-path solution between a pair of source and destination nodes. Unlike shortest-path routing or max-flow routing, for any given network topology - only one capillary routing solution exists. Capillary routing can be constructed by an iterative linear programming process, transforming a single-path flow into a capillary route. | https://en.wikipedia.org/wiki/Multipath_routing |
First minimize the maximal value of the load on all of the network routing node links Do that by minimizing a load upper bound value that is applied to all links. The full mass of the flow will be split equally across the possible parallel routes. Find the bottleneck links of the first layer (see below), then set their loading amount at the found minimum. | https://en.wikipedia.org/wiki/Multipath_routing |
Additionally, minimize the maximal load of all remaining links, but now without the bottleneck links of the first layer. This second iteration further refines the path diversity. Next, we determine the bottleneck links of the 2nd network layer. | https://en.wikipedia.org/wiki/Multipath_routing |
Again, minimize the maximal load of all remaining links, but now without the bottlenecks of the 2nd network layer as well. Repeat this algorithm until the entire communication footprint is enclosed in the bottlenecks of the constructed layers.At each functional layer of the network protocol, after minimizing the maximal load of links, the bottlenecks of the layer are discovered in a bottleneck detection process. At each iteration of the detection loop, we minimize the sending of traffic over all links having maximal loading, and being suspected as bottlenecks. Links unable to maintain their traffic load at the maximum are eventually removed from the candidate path list. The bottleneck detection process stops when there are no more links to remove, because this best path is now known. | https://en.wikipedia.org/wiki/Multipath_routing |
In networking equipment, maximum jumbo frame size may be specified using either maximum frame size (maximum layer 2 packet size, includes frame headers) or maximum transmission unit (maximum layer 3 packet size, excludes frame headers), depending on the equipment's configuration interface.A network that has a mixture of devices configured for jumbo frames and devices not configured for jumbo frames may have performance issues. | https://en.wikipedia.org/wiki/Jumbo_frame |
In networking jargon, a computer, phone, or internet of things device connected to a computer network is sometimes referred to as an end system or end station, because it sits at the edge of the network. The end user directly interacts with an end system that provides information or services.End systems that are connected to the Internet are also referred to as internet hosts; this is because they host (run) internet applications such as a web browser or an email retrieval program. The Internet's end systems include some computers with which the end user does not directly interact. These include mail servers, web servers, or database servers. | https://en.wikipedia.org/wiki/End_System |
With the emergence of the internet of things, household items (such as toasters and refrigerators) as well as portable, handheld computers and digital cameras are all being connected to the internet as end systems. End systems are generally connected to each other using switching devices known as routers rather than using a single communication link. The path that transmitted information takes from the sending end system, through a series of communications links and routers, to the receiving end system is known as a route or path through the network. | https://en.wikipedia.org/wiki/End_System |
The sending and receiving route can be different, and can be reallocated during transmission due to changes in the network topology. Normally the cheapest or fastest route is chosen. For the end user the actual routing should be completely transparent. | https://en.wikipedia.org/wiki/End_System |
In networking, Voronoi diagrams can be used in derivations of the capacity of a wireless network. In computer graphics, Voronoi diagrams are used to calculate 3D shattering / fracturing geometry patterns. It is also used to procedurally generate organic or lava-looking textures. In autonomous robot navigation, Voronoi diagrams are used to find clear routes. | https://en.wikipedia.org/wiki/Voronoi_diagrams |
If the points are obstacles, then the edges of the graph will be the routes furthest from obstacles (and theoretically any collisions). In machine learning, Voronoi diagrams are used to do 1-NN classifications. In global scene reconstruction, including with random sensor sites and unsteady wake flow, geophysical data, and 3D turbulence data, Voronoi tesselations are used with deep learning. In user interface development, Voronoi patterns can be used to compute the best hover state for a given point. | https://en.wikipedia.org/wiki/Voronoi_diagrams |
In networking, a black hole, also known as a block hole, refers to a place in the network where incoming or outgoing traffic is silently discarded (or "dropped"), without informing the source that the data did not reach its intended recipient. When examining the topology of the network, the black holes themselves are invisible, and can only be detected by monitoring the lost traffic; hence the name as astronomical black holes cannot be directly observed. | https://en.wikipedia.org/wiki/Blackhole_routing |
In networking, consider a distributed chat network like IRC, where a user who starts a channel automatically acquires channel-operator privileges. If two users on different servers, on different ends of the same network, try to start the same-named channel at the same time, each user's respective server will grant channel-operator privileges to each user, since neither server will yet have received the other server's signal that it has allocated that channel. (This problem has been largely solved by various IRC server implementations.) In this case of a race condition, the concept of the "shared resource" covers the state of the network (what channels exist, as well as what users started them and therefore have what privileges), which each server can freely change as long as it signals the other servers on the network about the changes so that they can update their conception of the state of the network. | https://en.wikipedia.org/wiki/Race_condition |
However, the latency across the network makes possible the kind of race condition described. In this case, heading off race conditions by imposing a form of control over access to the shared resource—say, appointing one server to control who holds what privileges—would mean turning the distributed network into a centralized one (at least for that one part of the network operation). Race conditions can also exist when a computer program is written with non-blocking sockets, in which case the performance of the program can be dependent on the speed of the network link. | https://en.wikipedia.org/wiki/Race_condition |
In networking, multipacket reception refers to the capability of networking nodes for decoding/demodulating signals from a number of source nodes concurrently. In wireless communications, Multipacket reception is achieved using physical layer technologies like orthogonal CDMA, MIMO and space–time codes. | https://en.wikipedia.org/wiki/Multipacket_reception |
In networking, packets are the key foundation for scheduling. There are many different types of packet travelling around network core every day, and they are treated totally different. For example, voice and video packets have higher priority than normal packets. In order to manage and distribute packet effectively, network devices also use input queue to determine which packet will be transmitted first. | https://en.wikipedia.org/wiki/Input_queue |
In networks where a logically centralized control is available over the forwarding state, for example, using software-defined networking, routing techniques can be used that aim to optimize global and network-wide performance metrics. This has been used by large internet companies that operate many data centers in different geographical locations attached using private optical links, examples of which include Microsoft's Global WAN, Facebook's Express Backbone, and Google's B4.Global performance metrics to optimize include maximizing network utilization, minimizing traffic flow completion times, maximizing the traffic delivered prior to specific deadlines and reducing the completion times of flows. Work on the later over private WAN discusses modeling routing as a graph optimization problem by pushing all the queuing to the end-points. The authors also propose a heuristic to solve the problem efficiently while sacrificing negligible performance. | https://en.wikipedia.org/wiki/Routing_algorithms |
In networks with unit capacities, a much stronger time bound holds. Each blocking flow can be found in O ( E ) {\displaystyle O(E)} time, and it can be shown that the number of phases does not exceed O ( E ) {\displaystyle O({\sqrt {E}})} and O ( V 2 / 3 ) {\displaystyle O(V^{2/3})} . Thus the algorithm runs in O ( min { V 2 / 3 , E 1 / 2 } E ) {\displaystyle O(\min\{V^{2/3},E^{1/2}\}E)} time.In networks that arise from the bipartite matching problem, the number of phases is bounded by O ( V ) {\displaystyle O({\sqrt {V}})} , therefore leading to the O ( V E ) {\displaystyle O({\sqrt {V}}E)} time bound. The resulting algorithm is also known as Hopcroft–Karp algorithm. More generally, this bound holds for any unit network — a network in which each vertex, except for source and sink, either has a single entering edge of capacity one, or a single outgoing edge of capacity one, and all other capacities are arbitrary integers. | https://en.wikipedia.org/wiki/Dinic's_algorithm |
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