Consensus (computer science)A fundamental problem in distributed computing and multi-agent systems is to achieve overall system reliability in the presence of a number of faulty processes. This often requires coordinating processes to reach consensus, or agree on some data value that is needed during computation. Example applications of consensus include agreeing on what transactions to commit to a database in which order, state machine replication, and atomic broadcasts.
Double-spendingDouble-spending is a fundamental flaw in a digital cash protocol in which the same single digital token can be spent more than once. Due to the nature of information space, in comparison to physical space (as in: valuable physical resources), a digital token (like a file) is inherently almost infinitely duplicable or falsifiable, leading to ownership of said token itself being undefinable unless declared so by a chosen authority. As with counterfeit money, such double-spending leads to inflation by creating a new amount of copied currency that did not previously exist.
TurkmenistanTurkmenistan (tɜːrkˈmɛnᵻstæn or ˌtɜːrkmɛnᵻˈstɑːn; Türkmenistan, tʏɾkmønʏˈθːɑːn) is a landlocked country in Central Asia bordered by Kazakhstan to the northwest, Uzbekistan to the north, east and northeast, Afghanistan to the southeast, Iran to the south and southwest and the Caspian Sea to the west. Ashgabat is the capital and largest city. It is one of the six independent Turkic states. The population is about seven million (according to the 17 December 2022 Census) and is thus the lowest of the Central Asian republics, and Turkmenistan is one of the most sparsely populated nations in Asia.
Hagia SophiaHagia Sophia ( 'Holy Wisdom'; Ayasofya; Hagía Sophía; Sancta Sapientia), officially the Hagia Sophia Mosque (Ayasofya-i Kebir Cami-i Şerifi), is a mosque and a major cultural and historical site in Istanbul, Turkey. The last of three church buildings to be successively erected on the site by the Eastern Roman Empire, it was completed in 537 AD. It was an Orthodox church until the Ottoman conquest of Constantinople in 1453, then a mosque until 1935, then a museum and then from 2020 a mosque again, as well as being a Roman Catholic cathedral for some decades after the Fourth Crusade of 1204.
TurkeyTurkey (Türkiye, ˈtyɾcije), officially the Republic of Türkiye (Türkiye Cumhuriyeti ˈtyɾcije dʒumˈhuːɾijeti), is a country located mainly on the Anatolian Peninsula in West Asia, with a small portion on the Balkan Peninsula in Southeast Europe. It borders the Black Sea to the north; Georgia to the northeast; Armenia, Azerbaijan, and Iran to the east; Iraq to the southeast; Syria and the Mediterranean Sea to the south; the Aegean Sea to the west; and Greece and Bulgaria to the northwest. Cyprus is off the south coast.
Proof of workProof of work (PoW) is a form of cryptographic proof in which one party (the prover) proves to others (the verifiers) that a certain amount of a specific computational effort has been expended. Verifiers can subsequently confirm this expenditure with minimal effort on their part. The concept was invented by Moni Naor and Cynthia Dwork in 1993 as a way to deter denial-of-service attacks and other service abuses such as spam on a network by requiring some work from a service requester, usually meaning processing time by a computer.
Balance of paymentsIn international economics, the balance of payments (also known as balance of international payments and abbreviated BOP or BoP) of a country is the difference between all money flowing into the country in a particular period of time (e.g., a quarter or a year) and the outflow of money to the rest of the world. These financial transactions are made by individuals, firms and government bodies to compare receipts and payments arising out of trade of goods and services.
E-commerce payment systemAn e-commerce payment system (or an electronic payment system) facilitates the acceptance of electronic payment for offline transfer, also known as a subcomponent of electronic data interchange (EDI), e-commerce payment systems have become increasingly popular due to the widespread use of the internet-based shopping and banking. Credit cards remain the most common forms of payment for e-commerce transactions. As of 2008, in North America, almost 90% of online retail transactions were made with this payment type.
International monetary systemAn international monetary system is a set of internationally agreed rules, conventions and supporting institutions that facilitate international trade, cross border investment and generally the reallocation of capital between states that have different currencies. It should provide means of payment acceptable to buyers and sellers of different nationalities, including deferred payment. To operate successfully, it needs to inspire confidence, to provide sufficient liquidity for fluctuating levels of trade, and to provide means by which global imbalances can be corrected.
Bitcoin networkThe Bitcoin network is a peer-to-peer network of nodes which implement the Bitcoin protocol. The protocol itself implements a highly available, public, and decentralized ledger. The nodes verify that each update to the ledger follows the rules of the Bitcoin protocol. Users broadcast cryptographically signed messages to the network using Bitcoin cryptocurrency wallet software. These messages are proposed transactions, changes to be made in the ledger. Each node has a copy of the ledger's entire transaction history.
Robust statisticsRobust statistics are statistics with good performance for data drawn from a wide range of probability distributions, especially for distributions that are not normal. Robust statistical methods have been developed for many common problems, such as estimating location, scale, and regression parameters. One motivation is to produce statistical methods that are not unduly affected by outliers. Another motivation is to provide methods with good performance when there are small departures from a parametric distribution.
Linear regressionIn statistics, linear regression is a linear approach for modelling the relationship between a scalar response and one or more explanatory variables (also known as dependent and independent variables). The case of one explanatory variable is called simple linear regression; for more than one, the process is called multiple linear regression. This term is distinct from multivariate linear regression, where multiple correlated dependent variables are predicted, rather than a single scalar variable.
Payment systemA payment system is any system used to settle financial transactions through the transfer of monetary value. This includes the institutions, payment instruments such as payment cards, people, rules, procedures, standards, and technologies that make its exchange possible. A common type of payment system, called an operational network, links bank accounts and provides for monetary exchange using bank deposits. Some payment systems also include credit mechanisms, which are essentially a different aspect of payment.
