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."
The origins of the city date back to the founding of a monastic establishment on the site of Bangor Cathedral by the Celtic saint Deiniol in the early 6th century AD. 'Bangor' itself is an old Welsh word for a wattled enclosure, such as the one that originally surrounded the cathedral site. The present cathedral is a somewhat more recent building and has been extensively modified throughout the centuries. While the building itself is not the oldest, and certainly not the biggest, the bishopric of Bangor is one of the oldest in the UK.
In 973, Iago, ruler of the Kingdom of Gwynedd, was usurped by Hywel, and requested help from Edgar, King of England, to restore his position. Edgar, with an army went to Bangor, and encouraged both Iago and Hywel to share the leadership of the realm. Asserting overall control however, Edgar confirmed liberties and endowments of the Bishop of Bangor, granting land and gifts. From 1284 until the 15th century, Bangor bishops were granted several charters permitting them to hold fairs and govern the settlement, later ones also confirming them as Lord of the Manor.
Bangor remained a small settlement until the start of the 18th century, when a political desire to enhance communications between England and Ireland via the London-Holyhead-Dublin corridor saw it designated as a post town in 1718. Growth was spurred by slate mining at nearby Bethesda, beginning in the 1770s by Richard Pennant, becoming one of the largest slate quarries in the world. The route between London and Holyhead was much improved by Thomas Telford building the A5 road, which runs through the centre of the city and over the Menai Suspension Bridge which was also completed by him in 1826. Bangor railway station opened in 1848.
A parliamentary borough was created in 1832 for Bangor, becoming a contributing Caernarfon out borough as its status grew due to further industry such as shipbuilding as well as travel, not just from Telford's road, but through tourism mainly from Liverpool via steamboat. It was also an ancient borough from earlier privileges granted to Bangor in medieval times, but an 1835 government report investigating municipal corporations concluded that this status was defunct and in name only. The borough was reformed in 1883 into a municipal borough.
Friars School was founded as a free grammar school in 1557, and the University College of North Wales (later Bangor University) was founded in 1884. In 1877, the former HMS Clio became a school ship, moored on the Menai Strait at Bangor, and had 260 pupils. Closed after the end of hostilities of World War I, she was sold for scrap and broken up in 1919.
In World War II, parts of the BBC evacuated to Bangor during the worst of the Blitz. The BBC continue to maintain facilities in the city (see Media).
In 2012, Bangor was the first ever city in the UK to impose, throughout its city centre, a night-time curfew on under-16s. The six-month trial was brought in by Gwynedd Council and North Wales police, but opposed by civil rights groups.
In 2021, Owen Hurcum was unanimously elected as mayor, making history as the youngest-ever mayor in Wales at 22, as well as the first ever non-binary mayor of any UK city.