Loess

Loess (/ˈloʊ.əs/, /ˈlʌs/, /ˈlɛs/, or UK /ˈlɜːrs/; from German Löss [lœs]) is a clastic, predominantly silt-sized sediment that is formed by the accumulation of wind-blown dust. It covers about 10% of the Earth's surface.

Loess is an aeolian sediment formed by the accumulation of wind-blown silt, typically in the 20–50 micrometer size range, twenty percent or less clay and the balance equal parts sand and silt that are loosely cemented by calcium carbonate. It is usually homogeneous and highly porous and is traversed by vertical capillaries that permit the sediment to fracture and form vertical bluffs.

The word loess, with connotations of origin by wind-deposited accumulation, came into English from German Löss ([lœs]), which can be traced back to Swiss German and is cognate with the English word loose and the German word los. It was first applied to Rhine River valley loess about 1821.

Properties

Loess is homogeneous, porous, friable, pale yellow or buff, slightly coherent, typically non-stratified and often calcareous. Loess grains are angular with little polishing or rounding and composed of crystals of quartz, feldspar, mica and other minerals. Loess can be described as a rich, dust-like soil.

Local regression

LOESS and LOWESS (locally weighted scatterplot smoothing) are two strongly related non-parametric regression methods that combine multiple regression models in a k-nearest-neighbor-based meta-model. "LOESS" is a later generalization of LOWESS; although it is not a true initialism, it may be understood as standing for "LOcal regrESSion".

LOESS and LOWESS thus build on "classical" methods, such as linear and nonlinear least squares regression. They address situations in which the classical procedures do not perform well or cannot be effectively applied without undue labor. LOESS combines much of the simplicity of linear least squares regression with the flexibility of nonlinear regression. It does this by fitting simple models to localized subsets of the data to build up a function that describes the deterministic part of the variation in the data, point by point. In fact, one of the chief attractions of this method is that the data analyst is not required to specify a global function of any form to fit a model to the data, only to fit segments of the data.

Hohn

Hohn may refer to:

People

Other uses

Hohn, Schleswig-Holstein

Hohn is a municipality in the district of Rendsburg-Eckernförde, in Schleswig-Holstein, Germany.

The location of Hohn is south of the municipality of Königshügel or Lohe-Föhrden, but north of Friedrichsgraben or Sophienhamm or Elsdorf-Westermühlen, and west of Fockbek.

References