Julius Ferdinand von Hann (23 March 1839 Linz

Linz

Linz is the third-largest city of Austria and capital of the state of Upper Austria . It is located in the north centre of Austria, approximately south of the Czech border, on both sides of the river Danube. The population of the city is , and that of the Greater Linz conurbation is about...

 – 1 October 1921 Vienna

Vienna

Vienna is the capital and largest city of the Republic of Austria and one of the nine states of Austria. Vienna is Austria's primary city, with a population of about 1.723 million , and is by far the largest city in Austria, as well as its cultural, economic, and political centre...

) was an Austria

Austria

Austria , officially the Republic of Austria , is a landlocked country of roughly 8.4 million people in Central Europe. It is bordered by the Czech Republic and Germany to the north, Slovakia and Hungary to the east, Slovenia and Italy to the south, and Switzerland and Liechtenstein to the...

n meteorologist

Meteorology

Meteorology is the interdisciplinary scientific study of the atmosphere. Studies in the field stretch back millennia, though significant progress in meteorology did not occur until the 18th century. The 19th century saw breakthroughs occur after observing networks developed across several countries...

. He is seen as the father of modern meteorology.

Biography

He was educated at the gymnasium

Gymnasium (school)

A gymnasium is a type of school providing secondary education in some parts of Europe, comparable to English grammar schools or sixth form colleges and U.S. college preparatory high schools. The word γυμνάσιον was used in Ancient Greece, meaning a locality for both physical and intellectual...

 of Kremsmünster

Kremsmünster

Kremsmünster is a town in Kirchdorf an der Krems , in Upper Austria, Austria. Its population is 6,450, as of 2001. Settled in 777, it is home to the Kremsmünster Abbey....

 and then studied mathematics

Mathematics

Mathematics is the study of quantity, space, structure, and change. Mathematicians seek out patterns and formulate new conjectures. Mathematicians resolve the truth or falsity of conjectures by mathematical proofs, which are arguments sufficient to convince other mathematicians of their validity...

, chemistry

Chemistry

Chemistry is the science of matter, especially its chemical reactions, but also its composition, structure and properties. Chemistry is concerned with atoms and their interactions with other atoms, and particularly with the properties of chemical bonds....

 and physics

Physics

Physics is a natural science that involves the study of matter and its motion through spacetime, along with related concepts such as energy and force. More broadly, it is the general analysis of nature, conducted in order to understand how the universe behaves.Physics is one of the oldest academic...

 at the University of Vienna

University of Vienna

The University of Vienna is a public university located in Vienna, Austria. It was founded by Duke Rudolph IV in 1365 and is the oldest university in the German-speaking world...

. From 1865 to 1868, he was master at the Oberrealschule at Linz, and in 1865 was appointed editor of the Zeitschrift für Meteorologie. In 1877, he became director of the Meteorologische Zentralanstalt (Central Institute for Meteorology) and professor of meteorology at the University of Vienna. In 1897, he became professor of meteorology at the University of Graz

Graz

The more recent population figures do not give the whole picture as only people with principal residence status are counted and people with secondary residence status are not. Most of the people with secondary residence status in Graz are students...

, but returned to Vienna to fill the chair of professor of cosmic physics in 1900, where he remained until 1910. In 1912, he was made a foreign knight of the Prussia

Prussia

Prussia was a German kingdom and historic state originating out of the Duchy of Prussia and the Margraviate of Brandenburg. For centuries, the House of Hohenzollern ruled Prussia, successfully expanding its size by way of an unusually well-organized and effective army. Prussia shaped the history...

n Ordre Pour le Mérite.

Hann window

In signal processing

Signal processing

Signal processing is an area of systems engineering, electrical engineering and applied mathematics that deals with operations on or analysis of signals, in either discrete or continuous time...

, the Hann window is a window function

Window function

In signal processing, a window function is a mathematical function that is zero-valued outside of some chosen interval. For instance, a function that is constant inside the interval and zero elsewhere is called a rectangular window, which describes the shape of its graphical representation...

, called the Hann function

Hann function

The Hann function, named after the Austrian meteorologist Julius von Hann, is a discrete probability mass function given byw= 0.5\; \leftorw= \sin^2 \left...

, named after him by R. B. Blackman and John Tukey

John Tukey

John Wilder Tukey ForMemRS was an American statistician.- Biography :Tukey was born in New Bedford, Massachusetts in 1915, and obtained a B.A. in 1936 and M.Sc. in 1937, in chemistry, from Brown University, before moving to Princeton University where he received a Ph.D...

in "Particular Pairs of Windows," published in "The Measurement of Power Spectra, From the Point of View of Communications Engineering", New York: Dover, 1959, pp. 98-99.

In the aforementioned article, the use of the Hann window is called "hanning", e.g., "hanning" a signal is to apply the Hann window to it.

Works

• Die Erde als Ganzes, ihre Atmosphäre und Hydrosphäre, 1872
• Handbuch der Klimatologie, 1883
• Atlas der Meteorologie, 1887
• Lehrbuch der Meteorologie, 1901

He contributed many papers to the Sitzungsberichte der Kaiserlichen Akademie der Wissenschaften.