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Wave Radar
Wave radar is a type of radar for measuring wind waves. Several instruments based on a variety of different concepts and techniques are available, and these are all often called. This article (see also #Reference-idGroenlie2004, Grønlie 2004), gives a brief description of the most common ground-based radar remote sensing techniques. Instruments based on radar remote sensing techniques have become of particular interest in applications where it is important to avoid direct contact with the water surface and avoid structural interference. A typical case is wave measurements from an offshore platform in deep water, where swift currents could make mooring a wave buoy enormously difficult. Another interesting case is a ship under way, where having instruments in the sea is highly impractical and interference from the ship's hull must be avoided. Radar remote sensing Terms and definitions Basically there are two different ''classes'' of radar remote sensors for ocean waves. * ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Middleware
Middleware is a type of computer software that provides services to software applications beyond those available from the operating system. It can be described as "software glue". Middleware makes it easier for software developers to implement communication and input/output, so they can focus on the specific purpose of their application. It gained popularity in the 1980s as a solution to the problem of how to link newer applications to older legacy systems, although the term had been in use since 1968. In distributed applications The term is most commonly used for software that enables communication and management of data in distributed applications. An IETF workshop in 2000 defined middleware as "those services found above the transport (i.e. over TCP/IP) layer set of services but below the application environment" (i.e. below application-level APIs). In this more specific sense ''middleware'' can be described as the dash ("-") in '' client-server'', or the ''-to-'' in ''peer ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Differential Equation
In mathematics, a differential equation is an equation that relates one or more unknown functions and their derivatives. In applications, the functions generally represent physical quantities, the derivatives represent their rates of change, and the differential equation defines a relationship between the two. Such relations are common; therefore, differential equations play a prominent role in many disciplines including engineering, physics, economics, and biology. Mainly the study of differential equations consists of the study of their solutions (the set of functions that satisfy each equation), and of the properties of their solutions. Only the simplest differential equations are solvable by explicit formulas; however, many properties of solutions of a given differential equation may be determined without computing them exactly. Often when a closed-form expression for the solutions is not available, solutions may be approximated numerically using computers. The theory of d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Least Squares Inversion
Comparison is a feature in the morphology or syntax of some languages whereby adjectives and adverbs are inflected to indicate the relative degree of the property they define exhibited by the word or phrase they modify or describe. In languages that have it, the comparative construction expresses quality, quantity, or degree relative to ''some'' other comparator(s). The superlative construction expresses the greatest quality, quantity, or degree—i.e. relative to ''all'' other comparators. The associated grammatical category is degree of comparison. The usual degrees of comparison are the ''positive'', which simply denotes a property (as with the English words ''big'' and ''fully''); the ''comparative'', which indicates ''greater'' degree (as ''bigger'' and ''more fully''); and the ''superlative'', which indicates ''greatest'' degree (as ''biggest'' and ''most fully''). Some languages have forms indicating a very large degree of a particular quality (called ''elative'' in Semit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geometry
Geometry (; ) is, with arithmetic, one of the oldest branches of mathematics. It is concerned with properties of space such as the distance, shape, size, and relative position of figures. A mathematician who works in the field of geometry is called a ''geometer''. Until the 19th century, geometry was almost exclusively devoted to Euclidean geometry, which includes the notions of point, line, plane, distance, angle, surface, and curve, as fundamental concepts. During the 19th century several discoveries enlarged dramatically the scope of geometry. One of the oldest such discoveries is Carl Friedrich Gauss' ("remarkable theorem") that asserts roughly that the Gaussian curvature of a surface is independent from any specific embedding in a Euclidean space. This implies that surfaces can be studied ''intrinsically'', that is, as stand-alone spaces, and has been expanded into the theory of manifolds and Riemannian geometry. Later in the 19th century, it appeared that geometries ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
X Band
The X band is the designation for a band of frequencies in the microwave radio region of the electromagnetic spectrum. In some cases, such as in communication engineering, the frequency range of the X band is rather indefinitely set at approximately 7.0–11.2 GHz. In radar engineering, the frequency range is specified by the Institute of Electrical and Electronics Engineers (IEEE) as 8.0–12.0 GHz. The X band is used for radar, satellite communication, and wireless computer networks. Radar X band is used in radar applications including continuous-wave, pulsed, single- polarization, dual-polarization, synthetic aperture radar, and phased arrays. X band radar frequency sub-bands are used in civil, military, and government institutions for weather monitoring, air traffic control, maritime vessel traffic control, defense tracking, and vehicle speed detection for law enforcement. X band is often used in modern radars. The shorter wavelengths of the X band allow ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sea Echo Image
The sea, connected as the world ocean or simply the ocean, is the body of water, body of saline water, salty water that covers approximately 71% of the Earth's surface. The word sea is also used to denote List of seas, second-order sections of the sea, such as the Mediterranean Sea, as well as certain large, entirely landlocked, saltwater lakes, such as the Caspian Sea. The sea moderates Earth's climate and has important roles in the water cycle, water, carbon cycle, carbon, and nitrogen cycle, nitrogen cycles. Humans harnessing and studying the sea have been recorded since ancient times, and evidenced well into prehistory, while its modern scientific study is called oceanography. The most abundant solid dissolved in seawater is sodium chloride. The water also contains salt (chemistry), salts of magnesium, calcium, potassium, and Mercury (element), mercury, amongst many other elements, some in minute concentrations. Salinity varies widely, being lower near the surface and the mo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
National Oceanic And Atmospheric Administration
The National Oceanic and Atmospheric Administration (abbreviated as NOAA ) is an United States scientific and regulatory agency within the United States Department of Commerce that forecasts weather, monitors oceanic and atmospheric conditions, charts the seas, conducts deep sea exploration, and manages fishing and protection of marine mammals and endangered species in the U.S. exclusive economic zone. Purpose and function NOAA's specific roles include: * ''Supplying Environmental Information Products''. NOAA supplies to its customers and partners information pertaining to the state of the oceans and the atmosphere, such as weather warnings and forecasts via the National Weather Service. NOAA's information services extend as well to climate, ecosystems, and commerce. * ''Providing Environmental Stewardship Services''. NOAA is a steward of U.S. coastal and marine environments. In coordination with federal, state, local, tribal and international authorities, NOAA manages the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tide
Tides are the rise and fall of sea levels caused by the combined effects of the gravity, gravitational forces exerted by the Moon (and to a much lesser extent, the Sun) and are also caused by the Earth and Moon orbiting one another. Tide tables can be used for any given locale to find the predicted times and amplitude (or "tidal range"). The predictions are influenced by many factors including the alignment of the Sun and Moon, the #Phase and amplitude, phase and amplitude of the tide (pattern of tides in the deep ocean), the amphidromic systems of the oceans, and the shape of the coastline and near-shore bathymetry (see ''#Timing, Timing''). They are however only predictions, the actual time and height of the tide is affected by wind and atmospheric pressure. Many shorelines experience semi-diurnal tides—two nearly equal high and low tides each day. Other locations have a diurnal cycle, diurnal tide—one high and low tide each day. A "mixed tide"—two uneven magnitude ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Continuous Wave Frequency Modulated
Continuous-wave radar (CW radar) is a type of radar system where a known stable frequency continuous wave radio energy is transmitted and then received from any reflecting objects. Individual objects can be detected using the Doppler effect, which causes the received signal to have a different frequency from the transmitted signal, allowing it to be detected by filtering out the transmitted frequency. Doppler-analysis of radar returns can allow the filtering out of slow or non-moving objects, thus offering immunity to interference from large stationary objects and slow-moving clutter. This makes it particularly useful for looking for objects against a background reflector, for instance, allowing a high-flying aircraft to look for aircraft flying at low altitude against the background of the surface. Because the very strong reflection off the surface can be filtered out, the much smaller reflection from a target can still be seen. CW radar systems are used at both ends of the range ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
