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Harold Edwin Hurst
Harold Edwin Hurst (1 January 1880 – 7 December 1978) was a British hydrology, hydrologist from Leicester. Hurst's (1951) study on measuring the long-term storage capacity of reservoirs documented the presence of long-range dependence in hydrology, especially concerning the fluctuations of the water level in the Nile River. In doing so, he developed the empirical rescaled range methodology for measuring long-range dependence. Much of Hurst's research was motivated by his empirical observations of the Nile. The Hurst exponent, which has been used in other fields, such as finance and cardiology, was named after him. His work in Egypt started in 1906 and lasted 62 years doing his best work after he reached 65. He championed the Aswan Dam#Aswan High Dam prelude, 1954–1960, prelude to the new Aswan High Dam project which was built using his plan. References *Benoît Mandelbrot, Mandelbrot, Benoît B., ''The (Mis)Behavior of Markets, A Fractal View of Risk, Ruin and Reward'' (Basic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrology
Hydrology () is the scientific study of the movement, distribution, and management of water on Earth and other planets, including the water cycle, water resources, and environmental watershed sustainability. A practitioner of hydrology is called a hydrologist. Hydrologists are scientists studying earth or environmental science, civil or environmental engineering, and physical geography. Using various analytical methods and scientific techniques, they collect and analyze data to help solve water related problems such as environmental preservation, natural disasters, and water management. Hydrology subdivides into surface water hydrology, groundwater hydrology (hydrogeology), and marine hydrology. Domains of hydrology include hydrometeorology, surface hydrology, hydrogeology, drainage-basin management, and water quality, where water plays the central role. Oceanography and meteorology are not included because water is only one of many important aspects within those fields. H ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Long-range Dependence
Long-range dependence (LRD), also called long memory or long-range persistence, is a phenomenon that may arise in the analysis of spatial or time series data. It relates to the rate of decay of statistical dependence of two points with increasing time interval or spatial distance between the points. A phenomenon is usually considered to have long-range dependence if the dependence decays more slowly than an exponential decay, typically a power-like decay. LRD is often related to self-similar processes or fields. LRD has been used in various fields such as internet traffic modelling, econometrics, hydrology, linguistics and the earth sciences. Different mathematical definitions of LRD are used for different contexts and purposes. Short-range dependence versus long-range dependence One way of characterising long-range and short-range dependent stationary process is in terms of their autocovariance functions. For a short-range dependent process, the coupling between values at differen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nile River
The Nile, , Bohairic , lg, Kiira , Nobiin: Áman Dawū is a major north-flowing river in northeastern Africa. It flows into the Mediterranean Sea. The Nile is the longest river in Africa and has historically been considered the longest river in the world, though this has been contested by research suggesting that the Amazon River is slightly longer.Amazon Longer Than Nile River, Scientists Say Of the world's major rivers, the Nile is one of the smallest, as measured by annual flow in cubic metres of water. About long, its covers eleven countries: the |
Rescaled Range
The rescaled range is a statistical measure of the variability of a time series introduced by the British hydrologist Harold Edwin Hurst (1880–1978). Its purpose is to provide an assessment of how the apparent variability of a series changes with the length of the time-period being considered. The rescaled range of time series is calculated from dividing the range of its mean adjusted cumulative deviate series (see the Calculation section below) by the standard deviation of the time series itself. For example, consider a time series , which has a mean m = 2 and standard deviation S = 1.79. Subtracting m from each value of the series gives mean adjusted series . To calculate cumulative deviate series we take the first value -1, then sum of the first two values -1+1=0, then sum of the first three values and so on to get , range of which is R = 3, so the rescaled range is R/S = 1.68. If we consider the same time series, but increase the number of observations of it, the rescaled ran ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hurst Exponent
The Hurst exponent is used as a measure of long-term memory of time series. It relates to the autocorrelations of the time series, and the rate at which these decrease as the lag between pairs of values increases. Studies involving the Hurst exponent were originally developed in hydrology for the practical matter of determining optimum dam sizing for the Nile river's volatile rain and drought conditions that had been observed over a long period of time. The name "Hurst exponent", or "Hurst coefficient", derives from Harold Edwin Hurst (1880–1978), who was the lead researcher in these studies; the use of the standard notation ''H'' for the coefficient also relates to his name. In fractal geometry, the generalized Hurst exponent has been denoted by ''H'' or ''Hq'' in honor of both Harold Edwin Hurst and Ludwig Otto Hölder (1859–1937) by Benoît Mandelbrot (1924–2010). ''H'' is directly related to fractal dimension, ''D'', and is a measure of a data series' "mild" or "wild" ra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aswan Dam
The Aswan Dam, or more specifically since the 1960s, the Aswan High Dam, is one of the world's largest embankment dams, which was built across the Nile in Aswan, Egypt, between 1960 and 1970. Its significance largely eclipsed the previous Aswan Low Dam initially completed in 1902 downstream. Based on the success of the Low Dam, then at its maximum utilization, construction of the High Dam became a key objective of the government following the Egyptian Revolution of 1952; with its ability to better control flooding, provide increased water storage for irrigation and generate hydroelectricity, the dam was seen as pivotal to Egypt's planned industrialization. Like the earlier implementation, the High Dam has had a significant effect on the economy and culture of Egypt. Before the High Dam was built, even with the old dam in place, the annual flooding of the Nile during late summer had continued to pass largely unimpeded down the valley from its East African drainage basin. These flo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Benoît Mandelbrot
Benoit B. Mandelbrot (20 November 1924 – 14 October 2010) was a Polish-born French-American mathematician and polymath with broad interests in the practical sciences, especially regarding what he labeled as "the art of roughness" of physical phenomena and "the uncontrolled element in life". He referred to himself as a "fractalist" and is recognized for his contribution to the field of fractal geometry, which included coining the word "fractal", as well as developing a theory of "roughness and self-similarity" in nature. In 1936, at the age of 11, Mandelbrot and his family emigrated from Warsaw, Poland, to France. After World War II ended, Mandelbrot studied mathematics, graduating from universities in Paris and in the United States and receiving a master's degree in aeronautics from the California Institute of Technology. He spent most of his career in both the United States and France, having dual French and American citizenship. In 1958, he began a 35-year career at ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1880 Births
Year 188 (CLXXXVIII) was a leap year starting on Monday of the Julian calendar. At the time, it was known in the Roman Empire as the Year of the Consulship of Fuscianus and Silanus (or, less frequently, year 941 ''Ab urbe condita''). The denomination 188 for this year has been used since the early medieval period, when the Anno Domini calendar era became the prevalent method in Europe for naming years. Events By place Roman Empire * Publius Helvius Pertinax becomes pro-consul of Africa from 188 to 189. Japan * Queen Himiko (or Shingi Waō) begins her reign in Japan (until 248). Births * April 4 – Caracalla (or Antoninus), Roman emperor (d. 217) * Lu Ji (or Gongji), Chinese official and politician (d. 219) * Sun Shao, Chinese general of the Eastern Wu state (d. 241) Deaths * March 17 – Julian, pope and patriarch of Alexandria * Fa Zhen (or Gaoqing), Chinese scholar (b. AD 100) * Lucius Antistius Burrus, Roman politician (executed) * Ma Xiang, Chin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1978 Deaths
Events January * January 1 – Air India Flight 855, a Boeing 747 passenger jet, crashes off the coast of Bombay, killing 213. * January 5 – Bülent Ecevit, of Republican People's Party, CHP, forms the new government of Turkey (42nd government). * January 6 – The Holy Crown of Hungary (also known as Stephen of Hungary Crown) is returned to Hungary from the United States, where it was held since World War II. * January 10 – Pedro Joaquín Chamorro Cardenal, a critic of the Nicaraguan government, is assassinated; riots erupt against Anastasio Somoza Debayle, Somoza's government. * January 18 – The European Court of Human Rights finds the British government guilty of mistreating prisoners in Northern Ireland, but not guilty of torture. * January 22 – Ethiopia declares the ambassador of West Germany ''persona non grata''. * January 24 ** Soviet Union, Soviet satellite Kosmos 954 burns up in Earth's atmosphere, scattering debris over Canada's Northwest Territories. ** ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
