Big data primarily refers to data sets that are too large or complex to be dealt with by traditional data-processing application software. Data with many entries (rows) offer greater statistical power, while data with higher complexity (more attributes or columns) may lead to a higher false discovery rate. Though used sometimes loosely partly because of a lack of formal definition, the interpretation that seems to best describe big data is the one associated with large body of information that we could not comprehend when used only in smaller amounts.
Big data analysis challenges include capturing data, data storage, data analysis, search, sharing, transfer, visualization, querying, updating, information privacy, and data source. Big data was originally associated with three key concepts: volume, variety, and velocity. The analysis of big data presents challenges in sampling, and thus previously allowing for only observations and sampling. Thus a fourth concept, veracity, refers to the quality or insightfulness of the data. Without sufficient investment in expertise for big data veracity, then the volume and variety of data can produce costs and risks that exceed an organization's capacity to create and capture value from big data.
Current usage of the term big data tends to refer to the use of predictive analytics, user behavior analytics, or certain other advanced data analytics methods that extract value from big data, and seldom to a particular size of data set. "There is little doubt that the quantities of data now available are indeed large, but that's not the most relevant characteristic of this new data ecosystem." Analysis of data sets can find new correlations to "spot business trends, prevent diseases, combat crime and so on". Scientists, business executives, medical practitioners, advertising and governments alike regularly meet difficulties with large data-sets in areas including Internet searches, fintech, healthcare analytics, geographic information systems, urban informatics, and business informatics. Scientists encounter limitations in e-Science work, including meteorology, genomics, connectomics, complex physics simulations, biology, and environmental research.
The size and number of available data sets have grown rapidly as data is collected by devices such as mobile devices, cheap and numerous information-sensing Internet of things devices, aerial (remote sensing), software logs, cameras, microphones, radio-frequency identification (RFID) readers and wireless sensor networks. The world's technological per-capita capacity to store information has roughly doubled every 40 months since the 1980s; as of 2012, every day 2.5 exabytes (2.5×260 bytes) of data are generated. Based on an IDC report prediction, the global data volume was predicted to grow exponentially from 4.4 zettabytes to 44 zettabytes between 2013 and 2020. By 2025, IDC predicts there will be 163 zettabytes of data. According to IDC, global spending on big data and business analytics (BDA) solutions is estimated to reach $215.7 billion in 2021. While Statista report, the global big data market is forecasted to grow to $103 billion by 2027. In 2011 McKinsey & Company reported, if US healthcare were to use big data creatively and effectively to drive efficiency and quality, the sector could create more than $300 billion in value every year. In the developed economies of Europe, government administrators could save more than €100 billion ($149 billion) in operational efficiency improvements alone by using big data. And users of services enabled by personal-location data could capture $600 billion in consumer surplus. One question for large enterprises is determining who should own big-data initiatives that affect the entire organization.
Relational database management systems and desktop statistical software packages used to visualize data often have difficulty processing and analyzing big data. The processing and analysis of big data may require "massively parallel software running on tens, hundreds, or even thousands of servers". What qualifies as "big data" varies depending on the capabilities of those analyzing it and their tools. Furthermore, expanding capabilities make big data a moving target. "For some organizations, facing hundreds of gigabytes of data for the first time may trigger a need to reconsider data management options. For others, it may take tens or hundreds of terabytes before data size becomes a significant consideration."
Ely (/ˈiːli/ (About this soundlisten) EE-lee) is a cathedral city in Cambridgeshire, England, about 14 miles (23 km) north-northeast of Cambridge and about 80 miles (129 km) by road from London. Æthelthryth (also known as Etheldreda) founded an abbey at Ely in 673; the abbey was destroyed in 870 by Danish invaders and was rebuilt by Æthelwold, Bishop of Winchester, in 970. Construction of the cathedral was started in 1083 by a Norman abbot, Simeon. Alan of Walsingham's octagon, built over Ely's nave crossing between 1322 and 1328, is the "greatest individual achievement of architectural genius at Ely Cathedral", according to architectural historian Nikolaus Pevsner. Building continued until the dissolution of the abbey in 1539 during the Reformation. The cathedral was sympathetically restored between 1845 and 1870 by the architect George Gilbert Scott. As the seat of a diocese, Ely has long been considered a city; in 1974, city status was granted by royal charter.
Ely is built on a 23-square-mile (60 km2) Kimmeridge Clay island which, at 85 feet (26 m), is the highest land in the Fens. Major rivers including the Witham, Welland, Nene and Great Ouse feed into the Fens and, until draining commenced in the 17th century, formed freshwater marshes and meres within which peat was laid down. There are two Sites of Special Scientific Interest in the city: a former Kimmeridge Clay quarry, and one of the United Kingdom's best remaining examples of medieval ridge and furrow agriculture.
The economy of the region is mainly agricultural. Before the Fens were drained, the harvesting of osier (willow) and sedge (rush) and the extraction of peat were important activities, as were eel fishing—from which the settlement's name may have been derived—and wildfowling. The city had been the centre of local pottery production for more than 700 years, including pottery known as Babylon ware. A Roman road, Akeman Street, passes through the city; the southern end is at Ermine Street near Wimpole and its northern end is at Brancaster. Little direct evidence of Roman occupation in Ely exists, although there are nearby Roman settlements such as those at Little Thetford and Stretham. A coach route, known to have existed in 1753 between Ely and Cambridge, was improved in 1769 as a turnpike (toll road). The present-day A10 closely follows this route; a southwestern bypass of the city was built in 1986. Ely railway station, built in 1845, is on the Fen Line and is now a railway hub, with lines north to King's Lynn, northwest to Peterborough, east to Norwich, southeast to Ipswich and south to Cambridge and London.
The King's School is a coeducational boarding school which was granted a royal charter in 1541 by Henry VIII; the school claims to have existed since 970. Henry I granted the first annual Fair, Saint Audrey's (or Etheldreda's) seven-day event, to the abbot and convent on 10 October 1189; the word "tawdry" originates from cheap lace sold at this fair. Present-day annual events include the Eel Festival in May, established in 2004, and a fireworks display in Ely Park, first staged in 1974. The city of Ely has been twinned with Denmark's oldest town, Ribe, since 1956. Ely City Football Club was formed in 1885.