Stratified
Stratification may refer to: Mathematics * Stratification (mathematics), any consistent assignment of numbers to predicate symbols * Data stratification in statistics Earth sciences * Stable and unstable stratification * Stratification, or stratum, the layering of rocks * Stratification (archeology), the formation of layers (strata) in which objects are found * Stratification (water), the formation of water layers based on temperature (and salinity, in oceans) * Lake stratification, the formation of water layers based on temperature, with mixing in the spring and fall in seasonal climates. * Atmospheric stratification, the dividing of the Earth's atmosphere into strata * Inversion (meteorology) Social sciences * Social stratification, the dividing of a society into levels based on power or socioeconomic status Biology * Stratification (seeds), where seeds are treated to simulate winter conditions so that germination may occur * Stratification (clinical trials), partitioning o ...
[...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]  

Stratified Sampling
In statistics, stratified sampling is a method of sampling from a population which can be partitioned into subpopulations. In statistical surveys, when subpopulations within an overall population vary, it could be advantageous to sample each subpopulation (stratum) independently. Stratification is the process of dividing members of the population into homogeneous subgroups before sampling. The strata should define a partition of the population. That is, it should be '' collectively exhaustive'' and '' mutually exclusive'': every element in the population must be assigned to one and only one stratum. Then simple random sampling is applied within each stratum. The objective is to improve the precision of the sample by reducing sampling error. It can produce a weighted mean that has less variability than the arithmetic mean of a simple random sample of the population. In computational statistics, stratified sampling is a method of variance reduction when Monte Carlo methods ...
[...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]  

Stratified Sampling
In statistics, stratified sampling is a method of sampling from a population which can be partitioned into subpopulations. In statistical surveys, when subpopulations within an overall population vary, it could be advantageous to sample each subpopulation (stratum) independently. Stratification is the process of dividing members of the population into homogeneous subgroups before sampling. The strata should define a partition of the population. That is, it should be ''collectively exhaustive'' and ''mutually exclusive'': every element in the population must be assigned to one and only one stratum. Then simple random sampling is applied within each stratum. The objective is to improve the precision of the sample by reducing sampling error. It can produce a weighted mean that has less variability than the arithmetic mean of a simple random sample of the population. In computational statistics, stratified sampling is a method of variance reduction when Monte Carlo methods are us ...
[...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]  

Fuel Stratified Injection
Gasoline direct injection (GDI), also known as petrol direct injection (PDI), is a mixture formation system for internal combustion engines that run on gasoline (petrol), where fuel is injected into the combustion chamber. This is distinct from manifold fuel injection systems, which inject fuel into the intake manifold. The use of GDI can help increase engine efficiency and specific power output as well as reduce exhaust emissions. The first GDI engine to reach production was introduced in 1925 for a low-compression truck engine. Several German cars used a Bosch mechanical GDI system in the 1950s, however usage of the technology remained rare until an electronic GDI system was introduced in 1996 by Mitsubishi for mass-produced cars. GDI has seen rapid adoption by the automotive industry in recent years, increasing in the United States from 2.3% of production for model year 2008 vehicles to approximately 50% for model year 2016. Operating principle Charge modes The 'charg ...
[...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]  

Stratification (clinical Trials)
Stratification of clinical trials is the partitioning of subjects and results by a factor other than the treatment given. Stratification can be used to ensure equal allocation of subgroups of participants to each experimental condition. This may be done by gender, age, or other demographic factors. Stratification can be used to control for confounding variables (variables other than those the researcher is studying), thereby making it easier for the research to detect and interpret relationships between variables. For example, if doing a study of fitness where age or gender was expected to influence the outcomes, participants could be stratified into groups by the confounding variable. A limitation of this method is that it requires knowledge of what variables need to be controlled. Types of stratification Stratified random sampling designs divide the population into homogeneous strata, and an appropriate number of participants are chosen at random from each stratum. Propor ...
[...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]  

Stratified Epithelial Lining (other)
Stratified epithelial lining can refer to: * Stratified squamous epithelium * Stratified columnar epithelium * Stratified cuboidal epithelium Stratified cuboidal epithelium is a type of epithelial tissue composed of multiple layers of cube-shaped cells. Only the most superficial layer is made up of cuboidal cells, and the other layers can be cells of other types. Topmost layer of skin ...

Stratification (water)
Stratification is the separation of water in layers. Two main types of stratification of water are uniform and layered stratification. Layered stratification occurs in all ocean basins. Stratified layers act as a barrier to the mixing of water, which impacts the exchange of heat, carbon, oxygen and other nutrients. Due to upwelling and downwelling, which are both wind-driven, mixing of different layers can occur through the rise of cold nutrient-rich and warm water, respectively. Generally, layers are based on water density: heavier, and hence denser, water is below the lighter water, representing a stable stratification. For example, the pycnocline is a layer in the ocean where the change in density is relatively large compared to that of other layers in the ocean. The thickness of the thermocline is not constant everywhere and depends on a variety of variables. Between 1960 and 2018, upper ocean stratification increased between 0.7-1.2% per decade. This means that the differenc ...
[...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]  

Stable And Unstable Stratification
Stable stratification of fluids occurs when each layer is less dense than the one below it. Unstable stratification is when each layer is denser than the one below it. Buoyancy forces tend to preserve stable stratification; the higher layers float on the lower ones. In unstable stratification, on the other hand, buoyancy forces cause convection. The less-dense layers rise though the denser layers above, and the denser layers sink though the less-dense layers below. Stratifications can become more or less stable if layers change density. The processes involved are important in many science and engineering fields. Destablization and mixing Stable stratifications can become unstable if layers change density. This can happen due to outside influences (for instance, if water evaporates from a freshwater lens, making it saltier and denser, or if a pot or layered beverage is heated from below, making the bottom layer less dense). However, it can also happen due to internal diffusi ...
[...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]  

Stratum
In geology and related fields, a stratum ( : strata) is a layer of rock or sediment characterized by certain lithologic properties or attributes that distinguish it from adjacent layers from which it is separated by visible surfaces known as either '' bedding surfaces'' or ''bedding planes''.Salvador, A. ed., 1994. ''International stratigraphic guide: a guide to stratigraphic classification, terminology, and procedure. 2nd ed.'' Boulder, Colorado, The Geological Society of America, Inc., 215 pp. . Prior to the publication of the International Stratigraphic Guide, older publications have defined a stratum as either being either equivalent to a single bed or composed of a number of beds; as a layer greater than 1 cm in thickness and constituting a part of a bed; or a general term that includes both ''bed'' and ''lamina''.Neuendorf, K.K.E., Mehl, Jr., J.P., and Jackson, J.A. , eds., 2005. ''Glossary of Geology'' 5th ed. Alexandria, Virginia, American Geological Institute. 779 pp. . ...
[...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]  

Strata (other)
Strata is the plural of stratum (the geological formation); for uses in the singular, see Stratum (other). Strata may also refer to: Media Music * Strata (band), a Northern California band * ''Strata'' (Matthew Shipp album), 1998 * ''Strata'' (Robert Rich and Steve Roach album), 1990 * ''Strata'' (Strata album), 2004 * Strata Records, a record label * Strata-East Records, a record label Printed media * Strata (comics), a superhero in the DC Universe * ''Strata'' (novel), a science fiction novel by Terry Pratchett Software * Kirix Strata, a web browser * Strata (company), a software company * Strata 3D, a 3D software * ''Strata'' (video game), a 2013 puzzle game * Strata, an IT certification from CompTIA Other uses * Strata (food), a family of layered casseroles * Strata (linguistics) * Strata roller coaster, a height classification, of roller coaster * Strata SE1, a building in London, England * Strata title, a form of ownership devised for multi-level a ...
[...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]  

Stratification (mathematics)
Stratification has several usages in mathematics. In mathematical logic In mathematical logic, stratification is any consistent assignment of numbers to Predicate (logic), predicate symbols guaranteeing that a unique formal Interpretation (logic), interpretation of a logical theory exists. Specifically, we say that a set of Clause (logic), clauses of the form Q_1 \wedge \dots \wedge Q_n \wedge \neg Q_ \wedge \dots \wedge \neg Q_ \rightarrow P is stratified if and only if there is a stratification assignment S that fulfills the following conditions: # If a predicate P is positively derived from a predicate Q (i.e., P is the head of a rule, and Q occurs positively in the body of the same rule), then the stratification number of P must be greater than or equal to the stratification number of Q, in short S(P) \geq S(Q). # If a predicate P is derived from a negated predicate Q (i.e., P is the head of a rule, and Q occurs negatively in the body of the same rule), then the stratification ...
[...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]  

Semantics
Semantics (from grc, σημαντικός ''sēmantikós'', "significant") is the study of reference, meaning, or truth. The term can be used to refer to subfields of several distinct disciplines, including philosophy Philosophy (from , ) is the systematized study of general and fundamental questions, such as those about existence, reason, knowledge, values, mind, and language. Such questions are often posed as problems to be studied or resolved. Some ..., linguistics and computer science. History In English, the study of meaning in language has been known by many names that involve the Ancient Greek word (''sema'', "sign, mark, token"). In 1690, a Greek rendering of the term ''semiotics'', the interpretation of signs and symbols, finds an early allusion in John Locke's ''An Essay Concerning Human Understanding'': The third Branch may be called [''simeiotikí'', "semiotics"], or the Doctrine of Signs, the most usual whereof being words, it is aptly enough ter ...
[...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]  

Destratification (other)
Destratification may refer to: * Thermal destratification, mixing air to reduce stratified layers of heat that become trapped near the ceiling in buildings * Lake stratification Lake stratification is the tendency of lakes to form separate and distinct thermal layers during warm weather. Typically stratified lakes show three distinct layers, the Epilimnion comprising the top warm layer, the thermocline (or Metalimnion) ...