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Russell Epstein | Russell Epstein | Russell Epstein is a professor of psychology at the University of Pennsylvania, who studies neural mechanisms underlying visual scene perception, event perception, object recognition, and spatial navigation in humans. His lab studies the role of the Parahippocampal and retrosplenial cortices in determining how people o... |
Russell Epstein | Education | Epstein received an undergraduate degree in physics at the University of Chicago and a Ph.D. in computer vision with Alan Yuille at Harvard. |
Ambient device | Ambient device | Ambient devices are a type of consumer electronics, characterized by their ability to be perceived at-a-glance, also known as "glanceable". Ambient devices use pre-attentive processing to display information and are aimed at minimizing mental effort. Associated fields include ubiquitous computing and calm technology. T... |
Ambient device | Purpose | The purpose of ambient devices is to enable immediate and effortless access to information. The original developers of the idea state that an ambient device is designed to provide support to people carrying out everyday activities. Ambient devices decrease the effort needed to process incoming data, thus rendering indi... |
Ambient device | History | The concept of ambient devices can be traced back to the early 2000s, when preliminary research was carried at Xerox PARC, according to the company’s official website. The MIT Media Lab website lists the venture as founded by David L. Rose, Ben Resner, Nabeel Hyatt and Pritesh Gandhi as a lab spin-off. |
Ambient device | Examples | Ambient Orb was introduced by Ambient Devices in 2002. The device was a glowing sphere that displayed data through changes in color. Ambient Orb was customizable in terms of content and its subsequent visual representation. For instance, when the device was set to monitor a stock market index (e.g. NASDAQ), the Orb glo... |
Ambient device | Examples | Another prominent ambient device is Chumby, released in 2008. It served as an at-a-glance widget station. Chumby was able to push relevant customizable data (weather, news, music, photos) to a touchscreen through Wi-Fi. It greatly surpassed the products resembling Ambient Orb, in terms of functionality, and was proclai... |
Electron excitation | Electron excitation | Electron excitation is the transfer of a bound electron to a more energetic, but still bound state. This can be done by photoexcitation (PE), where the electron absorbs a photon and gains all its energy or by collisional excitation (CE), where the electron receives energy from a collision with another, energetic electr... |
Electron excitation | Electron excitation in solids | Ground state preparation The energy and momentum of electrons in solids can be described by introducing Bloch waves into the Schrödinger equation with applying periodic boundary conditions. Solving this eigenvalue equation, one obtains sets of solutions that are describing bands of energies that are allowed to the elec... |
Electron excitation | Electron excitation in solids | Electron excitation by light: polariton The behavior of electrons excited by photons can be described by the quasi-particle named "polariton". A number of methods exist to describe these, both using classical and quantum electrodynamics. One of the methods is to use the concept of dressed particle. |
Addition chain | Addition chain | In mathematics, an addition chain for computing a positive integer n can be given by a sequence of natural numbers starting with 1 and ending with n, such that each number in the sequence is the sum of two previous numbers. The length of an addition chain is the number of sums needed to express all its numbers, which i... |
Addition chain | Examples | As an example: (1,2,3,6,12,24,30,31) is an addition chain for 31 of length 7, since 2 = 1 + 1 3 = 2 + 1 6 = 3 + 3 12 = 6 + 6 24 = 12 + 12 30 = 24 + 6 31 = 30 + 1Addition chains can be used for addition-chain exponentiation. This method allows exponentiation with integer exponents to be performed using a number of multi... |
Addition chain | Methods for computing addition chains | Calculating an addition chain of minimal length is not easy; a generalized version of the problem, in which one must find a chain that simultaneously forms each of a sequence of values, is NP-complete. There is no known algorithm which can calculate a minimal addition chain for a given number with any guarantees of rea... |
Addition chain | Chain length | Let l(n) denote the smallest s so that there exists an addition chain of length s which computes n It is known that log log 2.13 log log log log 2(n)) ,where ν(n) is the Hamming weight (the number of ones) of the binary expansion of n .One can obtain an addition chain for 2n from an addition chain for n by inc... |
Addition chain | Brauer chain | A Brauer chain or star addition chain is an addition chain in which each of the sums used to calculate its numbers uses the immediately previous number. A Brauer number is a number for which a Brauer chain is optimal.Brauer proved that l*(2n−1) ≤ n − 1 + l*(n)where l∗ is the length of the shortest star chain. For many... |
Addition chain | Scholz conjecture | The Scholz conjecture (sometimes called the Scholz–Brauer or Brauer–Scholz conjecture), named after Arnold Scholz and Alfred T. Brauer), is a conjecture from 1937 stating that l(2n−1)≤n−1+l(n).
This inequality is known to hold for all Hansen numbers, a generalization of Brauer numbers; Neill Clift checked by computer t... |
Frequency separation | Frequency separation | Frequency separation within astrophysics, is a term used in both Helioseismology and Asteroseismology. It refers to the spacing in frequency between adjacent modes of oscillation, having the same angular degree (l) but different radial order (n). |
Frequency separation | Frequency separation | For a Sun-like star, the frequency can be further described using the 'large frequency spacing' between modes of different radial order (136 μHz in the Sun), and the 'small frequency spacing' between modes of even and odd angular degree within the same radial order (9.0 μHz in the Sun). The period corresponding to the ... |
Kaon | Kaon | In particle physics, a kaon (), also called a K meson and denoted K, is any of a group of four mesons distinguished by a quantum number called strangeness. In the quark model they are understood to be bound states of a strange quark (or antiquark) and an up or down antiquark (or quark). |
Kaon | Kaon | Kaons have proved to be a copious source of information on the nature of fundamental interactions since their discovery in cosmic rays in 1947. They were essential in establishing the foundations of the Standard Model of particle physics, such as the quark model of hadrons and the theory of quark mixing (the latter was... |
Kaon | Basic properties | The four kaons are : K−, negatively charged (containing a strange quark and an up antiquark) has mass 493.677±0.013 MeV and mean lifetime (1.2380±0.0020)×10−8 s.
K+ (antiparticle of above) positively charged (containing an up quark and a strange antiquark) must (by CPT invariance) have mass and lifetime equal to that o... |
Kaon | Basic properties | K0, neutrally charged (antiparticle of above) (containing a strange quark and a down antiquark) has the same mass.As the quark model shows, assignments that the kaons form two doublets of isospin; that is, they belong to the fundamental representation of SU(2) called the 2. One doublet of strangeness +1 contains the K+... |
Kaon | Basic properties | [*] See Notes on neutral kaons in the article List of mesons, and neutral kaon mixing, below.[§]^ Strong eigenstate. No definite lifetime (see neutral kaon mixing).[†]^ Weak eigenstate. Makeup is missing small CP–violating term (see neutral kaon mixing).[‡]^ The mass of the K0L and K0S are given as that of the K0. Howe... |
Kaon | Basic properties | The short-lived neutral kaon is called the KS ("K-short"), decays primarily into two pions, and has a mean lifetime 8.958×10−11 s.(See discussion of neutral kaon mixing below.) An experimental observation made in 1964 that K-longs rarely decay into two pions was the discovery of CP violation (see below).
Main decay mod... |
Kaon | Parity violation | Two different decays were found for charged strange mesons: The intrinsic parity of a pion is P = −1, and parity is a multiplicative quantum number. Therefore, the two final states have different parity (P = +1 and P = −1, respectively). It was thought that the initial states should also have different parities, and he... |
Kaon | History | The discovery of hadrons with the internal quantum number "strangeness" marks the beginning of a most exciting epoch in particle physics that even now, fifty years later, has not yet found its conclusion ... by and large experiments have driven the development, and that major discoveries came unexpectedly or even again... |
Kaon | History | In 1949, Rosemary Brown (later Rosemary Fowler), a research student in C.F. Powell's Bristol group, spotted her 'k' track, made by a particle of very similar mass that decayed to three pions.(p82) This led to the so-called 'Tau-Theta' problem: What seemed to be the same particles (now called K+) decayed in two differen... |
Kaon | History | The first breakthrough was obtained at Caltech, where a cloud chamber was taken up Mount Wilson, for greater cosmic ray exposure. In 1950, 30 charged and 4 neutral "V-particles" were reported. Inspired by this, numerous mountaintop observations were made over the next several years, and by 1953, the following terminolo... |
Kaon | History | Leprince-Rinquet coined the still-used term "hyperon" to mean any particle heavier than a nucleon. The Leprince-Ringuet particle turned out to be the K+ meson.The decays were extremely slow; typical lifetimes are of the order of 10−10 s. However, production in pion-proton reactions proceeds much faster, with a time sca... |
Kaon | CP violation in neutral meson oscillations | Initially it was thought that although parity was violated, CP (charge parity) symmetry was conserved. In order to understand the discovery of CP violation, it is necessary to understand the mixing of neutral kaons; this phenomenon does not require CP violation, but it is the context in which CP violation was first obs... |
Kaon | CP violation in neutral meson oscillations | Neutral kaon mixing Since neutral kaons carry strangeness, they cannot be their own antiparticles. There must be then two different neutral kaons, differing by two units of strangeness. The question was then how to establish the presence of these two mesons. The solution used a phenomenon called neutral particle oscill... |
Kaon | CP violation in neutral meson oscillations | These oscillations were first investigated by Murray Gell-Mann and Abraham Pais together. They considered the CP-invariant time evolution of states with opposite strangeness. In matrix notation one can write ψ(t)=U(t)ψ(0)=eiHt(ab),H=(MΔΔM), where ψ is a quantum state of the system specified by the amplitudes of being i... |
Kaon | CP violation in neutral meson oscillations | The consequence of the matrix H being real is that the probabilities of the two states will forever oscillate back and forth. However, if any part of the matrix were imaginary, as is forbidden by CP symmetry, then part of the combination will diminish over time. The diminishing part can be either one component (a) or t... |
Kaon | CP violation in neutral meson oscillations | Mixing The eigenstates are obtained by diagonalizing this matrix. This gives new eigenvectors, which we can call K1 which is the difference of the two states of opposite strangeness, and K2, which is the sum. The two are eigenstates of CP with opposite eigenvalues; K1 has CP = +1, and K2 has CP = -1 Since the two-pion ... |
Kaon | CP violation in neutral meson oscillations | These two weak eigenstates are called the KL (K-long, τ) and KS (K-short, θ). CP symmetry, which was assumed at the time, implies that KS = K1 and KL = K2. |
Kaon | CP violation in neutral meson oscillations | Oscillation An initially pure beam of K0 will turn into its antiparticle, K0, while propagating, which will turn back into the original particle, K0, and so on. This is called particle oscillation. On observing the weak decay into leptons, it was found that a K0 always decayed into a positron, whereas the antiparticle ... |
Kaon | CP violation in neutral meson oscillations | Regeneration A beam of neutral kaons decays in flight so that the short-lived KS disappears, leaving a beam of pure long-lived KL. If this beam is shot into matter, then the K0 and its antiparticle K0 interact differently with the nuclei. The K0 undergoes quasi-elastic scattering with nucleons, whereas its antiparticle... |
Kaon | CP violation in neutral meson oscillations | CP violation While trying to verify Adair's results, J. Christenson, James Cronin, Val Fitch and Rene Turlay of Princeton University found decays of KL into two pions (CP = +1) in an experiment performed in 1964 at the Alternating Gradient Synchrotron at the Brookhaven laboratory. As explained in an earlier section, th... |
Kaon | CP violation in neutral meson oscillations | It turns out that although the KL and KS are weak eigenstates (because they have definite lifetimes for decay by way of the weak force), they are not quite CP eigenstates. Instead, for small ε (and up to normalization), KL = K2 + εK1and similarly for KS. Thus occasionally the KL decays as a K1 with CP = +1, and likewis... |
Twist (cocktail garnish) | Twist (cocktail garnish) | A twist is a piece of citrus zest used as a cocktail garnish, generally for decoration and to add flavor when added to a mixed drink. |
Twist (cocktail garnish) | Twist (cocktail garnish) | There are a variety of ways of making and using twists. Twists are typically cut from a whole fresh citrus fruit with a small kitchen knife immediately prior to serving, although a peeler, citrus zesters, or other utensil may be used. A curled shape may come from cutting the wedge into a spiral, winding it around a str... |
Twist (cocktail garnish) | Twist (cocktail garnish) | The name may refer to the shape of the garnish, which is typically curled or twisted longitudinally, or else to the act of twisting the garnish to release fruit oils that infuse the drink. Other techniques include running the twist along the rim of the glass, and "flaming" the twist.They are generally about 50 mm (2 in... |
Registered user | Registered user | A registered user is a user of a website, program, or other systems who has previously registered. Registered users normally provide some sort of credentials (such as a username or e-mail address, and a password) to the system in order to prove their identity: this is known as logging in. Systems intended for use by th... |
Registered user | Rationale | User registration and login enables a system to personalize itself. For example, a website might display a welcome banner with the user's name and change its appearance or behavior according to preferences indicated by the user. The system may also allow a logged-in user to send and receive messages, and to view and mo... |
Registered user | Criticism | Privacy concerns Registration necessarily provides more personal information to a system than it would otherwise have. Even if the credentials used are otherwise meaningless, the system can distinguish a logged-in user from other users and might use this property to store a history of users' actions or activity, possib... |
Registered user | Criticism | A system could even sell information it has gathered on its users to third parties for advertising or other purposes. The subject of systems' transparency in this regard is one of ongoing debate. |
Registered user | Criticism | User inconvenience Registration may be seen as an annoyance or hindrance, especially if it is not inherently necessary or important (for example, in the context of a search engine) or if the system repeatedly prompts users to register. A system's registration process might also be time-consuming or require that the use... |
Parabolic antenna | Parabolic antenna | A parabolic antenna is an antenna that uses a parabolic reflector, a curved surface with the cross-sectional shape of a parabola, to direct the radio waves. The most common form is shaped like a dish and is popularly called a dish antenna or parabolic dish. The main advantage of a parabolic antenna is that it has high ... |
Parabolic antenna | Parabolic antenna | Parabolic antennas are used as high-gain antennas for point-to-point communications, in applications such as microwave relay links that carry telephone and television signals between nearby cities, wireless WAN/LAN links for data communications, satellite communications, and spacecraft communication antennas. They are ... |
Parabolic antenna | Parabolic antenna | The other large use of parabolic antennas is for radar antennas, which need to transmit a narrow beam of radio waves to locate objects like ships, airplanes, and guided missiles. They are also often used for weather detection. With the advent of home satellite television receivers, parabolic antennas have become a comm... |
Parabolic antenna | Design | The operating principle of a parabolic antenna is that a point source of radio waves at the focal point in front of a paraboloidal reflector of conductive material will be reflected into a collimated plane wave beam along the axis of the reflector. Conversely, an incoming plane wave parallel to the axis will be focused... |
Parabolic antenna | Design | A typical parabolic antenna consists of a metal parabolic reflector with a small feed antenna suspended in front of the reflector at its focus, pointed back toward the reflector. The reflector is a metallic surface formed into a paraboloid of revolution and usually truncated in a circular rim that forms the diameter of... |
Parabolic antenna | Design | Parabolic reflector The reflector can be constructed from sheet metal, a metal screen, or a wire grill, and can be either a circular dish or various other shapes to create different beam shapes. A metal screen reflects radio waves as effectively as a solid metal surface if its holes are smaller than one-tenth of a wave... |
Parabolic antenna | Design | A reflector made of a grill of parallel wires or bars oriented in one direction acts as a polarizing filter as well as a reflector. It only reflects linearly polarized radio waves, with the electric field parallel to the grill elements. This type is often used in radar antennas. Combined with a linearly polarized feed ... |
Parabolic antenna | Design | A shiny metal parabolic reflector can also focus the sun's rays. Since most dishes could concentrate enough solar energy on the feed structure to severely overheat it if they happened to be pointed at the sun, solid reflectors are always given a coat of flat paint. |
Parabolic antenna | Design | Feed antenna The feed antenna at the reflector's focus is typically a low-gain type, such as a half-wave dipole or (more often) a small horn antenna called a feed horn. In more complex designs, such as the Cassegrain and Gregorian, a secondary reflector is used to direct the energy into the parabolic reflector from a f... |
Parabolic antenna | Design | At the microwave frequencies used in many parabolic antennas, waveguide is required to conduct the microwaves between the feed antenna and transmitter or receiver. Because of the high cost of waveguide runs, in many parabolic antennas the RF front end electronics of the receiver is located at the feed antenna, and the ... |
Parabolic antenna | Design | An advantage of parabolic antennas is that most of the structure of the antenna (all of it except the feed antenna) is nonresonant, so it can function over a wide range of frequencies (i.e. a wide bandwidth). All that is necessary to change the frequency of operation is to replace the feed antenna with one that operate... |
Parabolic antenna | Types | Parabolic antennas are distinguished by their shapes: Paraboloidal or dish – The reflector is shaped like a paraboloid truncated with a circular rim. This is the most common type. It radiates a narrow pencil-shaped beam along the axis of the dish. |
Parabolic antenna | Types | Shrouded dish – Sometimes a cylindrical metal shield is attached to the rim of the dish. The shroud shields the antenna from radiation from angles outside the main beam axis, reducing the sidelobes. It is sometimes used to prevent interference in terrestrial microwave links, where several antennas using the same freque... |
Parabolic antenna | Types | Cylindrical – The reflector is curved in only one direction and flat in the other. The radio waves come to a focus not at a point but along a line. The feed is sometimes a dipole antenna located along the focal line. Cylindrical parabolic antennas radiate a fan-shaped beam, narrow in the curved dimension, and wide in t... |
Parabolic antenna | Types | Shaped-beam antennas – Modern reflector antennas can be designed to produce a beam or beams of a particular shape, rather than just the narrow "pencil" or "fan" beams of the simple dish and cylindrical antennas mentioned above. Two techniques are used, often in combination, to control the shape of the beam: Shaped refl... |
Parabolic antenna | Types | "Orange peel" antenna – Used in search radars, this is a long narrow antenna shaped like the letter "C". It radiates a narrow vertical fan-shaped beam.Arrays of feeds – In order to produce an arbitrary shaped beam, instead of one feed horn, an array of feed horns clustered around the focal point can be used. Array-fed ... |
Parabolic antenna | Types | Off-axis or offset feed – The reflector is an asymmetrical segment of a paraboloid, so the focus, and the feed antenna, are located to one side of the dish. The purpose of this design is to move the feed structure out of the beam path, so it does not block the beam. It is widely used in home satellite television dishes... |
Parabolic antenna | Types | Cassegrain – In a Cassegrain antenna, the feed is located on or behind the dish, and radiates forward, illuminating a convex hyperboloidal secondary reflector at the focus of the dish. The radio waves from the feed reflect off the secondary reflector to the dish, which reflects them forward again, forming the outgoing ... |
Parabolic antenna | Types | Gregorian – Similar to the Cassegrain design except that the secondary reflector is concave (ellipsoidal) in shape. Aperture efficiency over 70% can be achieved. |
Parabolic antenna | Feed pattern | The radiation pattern of the feed antenna has to be tailored to the shape of the dish, because it has a strong influence on the aperture efficiency, which determines the antenna gain (see Gain section below). Radiation from the feed that falls outside the edge of the dish is called spillover and is wasted, reducing the... |
Parabolic antenna | Feed pattern | Polarization The pattern of electric and magnetic fields at the mouth of a parabolic antenna is simply a scaled-up image of the fields radiated by the feed antenna, so the polarization is determined by the feed antenna. In order to achieve maximum gain, both feed antennas (transmitting and receiving) must have the same... |
Parabolic antenna | Feed pattern | To increase the data rate, some parabolic antennas transmit two separate radio channels on the same frequency with orthogonal polarizations, using separate feed antennas; this is called a dual polarization antenna. For example, satellite television signals are transmitted from the satellite on two separate channels at ... |
Parabolic antenna | Feed pattern | If the signal from one polarization channel is received by the oppositely polarized antenna, it will cause crosstalk that degrades the signal-to-noise ratio. The ability of an antenna to keep these orthogonal channels separate is measured by a parameter called cross polarization discrimination (XPD). In a transmitting ... |
Parabolic antenna | Feed pattern | Dual reflector shaping In the Cassegrain and Gregorian antennas, the presence of two reflecting surfaces in the signal path offers additional possibilities for improving performance. When the highest performance is required, a technique called dual reflector shaping may be used. This involves changing the shape of the ... |
Parabolic antenna | Gain | The directive qualities of an antenna are measured by a dimensionless parameter called its gain, which is the ratio of the power received by the antenna from a source along its beam axis to the power received by a hypothetical isotropic antenna. The gain of a parabolic antenna is: G=4πAλ2eA=(πdλ)2eA where: A is the are... |
Parabolic antenna | Gain | d is the diameter of the parabolic reflector, if it is circular.
λ is the wavelength of the radio waves. |
Parabolic antenna | Gain | eA is a dimensionless parameter between 0 and 1 called the aperture efficiency. The aperture efficiency of typical parabolic antennas is 0.55 to 0.70.It can be seen that, as with any aperture antenna, the larger the aperture is, compared to the wavelength, the higher the gain. The gain increases with the square of the ... |
Parabolic antenna | Gain | Aperture efficiency eA is a catchall variable which accounts for various losses that reduce the gain of the antenna from the maximum that could be achieved with the given aperture. The major factors reducing the aperture efficiency in parabolic antennas are: Feed spillover – Some of the radiation from the feed antenna ... |
Parabolic antenna | Gain | Feed illumination taper – The maximum gain for any aperture antenna is only achieved when the intensity of the radiated beam is constant across the entire aperture area. However, the radiation pattern from the feed antenna usually tapers off toward the outer part of the dish, so the outer parts of the dish are "illumin... |
Parabolic antenna | Gain | Aperture blockage – In front-fed parabolic dishes where the feed antenna is located in front of the dish in the beam path (and in Cassegrain and Gregorian designs as well), the feed structure and its supports block some of the beam. In small dishes such as home satellite dishes, where the size of the feed structure is ... |
Parabolic antenna | Gain | Shape errors – Random surface errors in the shape of the reflector reduce efficiency. This loss is approximated by Ruze's Equation.For theoretical considerations of mutual interference (at frequencies between 2 and approximately 30 GHz; typically in the Fixed Satellite Service) where specific antenna performance has no... |
Parabolic antenna | Radiation pattern | In parabolic antennas, virtually all the power radiated is concentrated in a narrow main lobe along the antenna's axis. The residual power is radiated in sidelobes, usually much smaller, in other directions. Since the reflector aperture of parabolic antennas is much larger than the wavelength, diffraction usually cause... |
Parabolic antenna | Radiation pattern | Beamwidth The angular width of the beam radiated by high-gain antennas is measured by the half-power beam width (HPBW), which is the angular separation between the points on the antenna radiation pattern at which the power drops to one-half (-3 dB) its maximum value. For parabolic antennas, the HPBW θ is given by: θ=kλ... |
Parabolic antenna | Radiation pattern | There is an inverse relation between gain and beam width. By combining the beamwidth equation with the gain equation, the relation is: G=(πkθ)2eA Radiation pattern formula The radiation from a large paraboloid with uniform illuminated aperture is essentially equivalent to that from a circular aperture of the same diame... |
Parabolic antenna | Radiation pattern | E=∫∫Ar1ej(ωt−βr1)dS=∫∫e2πi(lx+my)/λdS where β=ω/c=2π/λ . Using polar coordinates, cos θ and sin θ . Taking account of symmetry, cos θl/λρdρ and using first-order Bessel function gives the electric field pattern E(θ) where D is the diameter of the antenna's aperture in meters, λ is the wavelength in meters, θ ... |
Parabolic antenna | History | The idea of using parabolic reflectors for radio antennas was taken from optics, where the power of a parabolic mirror to focus light into a beam has been known since classical antiquity. The designs of some specific types of parabolic antenna, such as the Cassegrain and Gregorian, come from similarly named analogous t... |
Parabolic antenna | History | Italian radio pioneer Guglielmo Marconi used a parabolic reflector during the 1930s in investigations of UHF transmission from his boat in the Mediterranean. In 1931, a 1.7 GHz microwave relay telephone link across the English Channel was demonstrated using 3.0-meter (10 ft) diameter dishes. The first large parabolic a... |
Parabolic antenna | History | During the 1960s, dish antennas became widely used in terrestrial microwave relay communication networks, which carried telephone calls and television programs across continents. The first parabolic antenna used for satellite communications was constructed in 1962 at Goonhilly in Cornwall, England, to communicate with ... |
Learning engineering | Learning engineering | Learning Engineering is the systematic application of evidence-based principles and methods from educational technology and the learning sciences to create engaging and effective learning experiences, support the difficulties and challenges of learners as they learn, and come to better understand learners and learning.... |
Learning engineering | Learning engineering | Supporting learners as they learn is complex, and design of learning experiences and support for learners usually requires interdisciplinary teams. Learning engineers themselves might specialize in designing learning experiences that unfold over time, engage the population of learners, and support their learning; autom... |
Learning engineering | Learning engineering | Learning engineering teams employ an iterative design process for supporting and improving learning. Initial designs are informed by findings from the learning sciences. Refinements are informed by analysis of data collected as designs are carried out in the world. Methods from learning analytics, design-based research... |
Learning engineering | History | Herbert Simon, a cognitive psychologist and economist, first coined the term learning engineering in 1967. However, associations between the two terms learning and engineering began emerging earlier, in the 1940s and as early as the 1920s. Simon argued that the social sciences, including the field of education, should ... |
Learning engineering | Overview | Learning Engineering is aimed at addressing a deficit in the application of science and engineering methodologies to education and training. Its advocates emphasize the need to connect computing technology and generated data with the overall goal of optimizing learning environments.Learning Engineering initiatives aim ... |
Learning engineering | Overview | This data enables educators to spot struggling students weeks or months prior to being in danger of dropping out. Proponents of Learning Engineering posit that data analytics will contribute to higher success rates and lower drop-out rates.Learning Engineering can also assist students by providing automatic and individ... |
Learning engineering | Common approaches | A/B Testing A/B testing compares two versions of a given program and allows researchers to determine which approach is most effective. In the context of Learning Engineering, platforms like TeacherASSIST and Coursera use A/B testing to determine which type of feedback is the most effective for learning outcomes.Neil He... |
Learning engineering | Common approaches | Educational Data Mining Educational Data Mining involves analyzing data from student use of educational software to understand how software can improve learning for all students. Researchers in the field, such as Ryan Baker at the University of Pennsylvania, have developed models of student learning, engagement, and af... |
Learning engineering | Common approaches | Learning Engineering in Practice Combining education theory with data analytics has contributed to the development of tools that differentiate between when a student is wheel spinning (i.e., not mastering a skill within a set timeframe) and when they are persisting productively. Tools like ASSISTments alert teachers wh... |
Learning engineering | Common approaches | Studies have found that Learning Engineering may help students and educators to plan their studies before courses begin. For example, UC Berkeley Professor Zach Pardos uses Learning Engineering to help reduce stress for community college students matriculating into four-year institutions. Their predictive model analyze... |
Learning engineering | Criticisms of Learning Engineering | Researchers and educational technology commentators have published critiques of learning engineering. The criticisms raised include that learning engineering misrepresents the field of learning sciences and that despite stating it is based on cognitive science, it actually resembles a return to behaviorism. Others have... |
Learning engineering | Criticisms of Learning Engineering | Still others have commented critically on learning engineering's use of metaphors and figurative language. Often a term or metaphor carries a different meaning for professionals or academics from different domains. At times a term that is used positively in one domain carries a strong negative perception in another dom... |
Learning engineering | Challenges for Learning Engineering Teams | The multidisciplinary nature of learning engineering creates challenges. The problems that learning engineering attempts to solve often require expertise in diverse fields such as software engineering, instructional design, domain knowledge, pedagogy/andragogy, psychometrics, learning sciences, data science, and system... |
Middle reliever | Middle reliever | In baseball, a middle reliever or middle relief pitcher, is a relief pitcher who typically pitches during the fifth, sixth, and seventh innings of a standard baseball game. In leagues with no designated hitter, such as in the National League prior to 2022 and the Japanese Central League, a middle reliever often comes i... |
Nested transaction | Nested transaction | A nested transaction is a database transaction that is started by an instruction within the scope of an already started transaction.
Nested transactions are implemented differently in different databases. However, they have in common that the changes are not made visible to any unrelated transactions until the outermos... |
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