Philosophy Chapter
Ryan Merkle QMRIn mathematics, four-dimensional space ("4D") is a geometric space with four dimensions. It typically is more specifically four-dimensional Euclidean space, generalizing the rules of three-dimensional Euclidean space. It has been studied by mathematicians and philosophers for over two centuries, both for its own interest and for the insights it offered into mathematics and related fields.
Algebraically, it is generated by applying the rules of vectors and coordinate geometry to a space with four dimensions. In particular a vector with four elements (a 4-tuple) can be used to represent a position in four-dimensional space. The space is a Euclidean space, so has a metric and norm, and so all directions are treated as the same: the additional dimension is indistinguishable from the other three.
In modern physics, space and time are unified in a four-dimensional Minkowski continuum called spacetime, whose metric treats the time dimension differently from the three spatial dimensions (see below for the definition of the Minkowski metric/pairing). Spacetime is not a Euclidean space.
History[edit]
See also: n-dimensional space § History
Lagrange wrote in his Mécanique analytique (published 1788, based on work done around 1755) that mechanics can be viewed as operating in a four-dimensional space — three of dimensions of space, and one of time.[1] In 1827 Möbius realized that a fourth dimension would allow a three-dimensional form to be rotated onto its mirror-image,[2] and by 1853 Ludwig Schläfli had discovered many polytopes in higher dimensions, although his work was not published until after his death.[3] Higher dimensions were soon put on firm footing by Bernhard Riemann's 1854 Habilitationsschrift, Über die Hypothesen welche der Geometrie zu Grunde liegen, in which he considered a "point" to be any sequence of coordinates (x1, ..., xn). The possibility of geometry in higher dimensions, including four dimensions in particular, was thus established.
An arithmetic of four dimensions called quaternions was defined by William Rowan Hamilton in 1843. This associative algebra was the source of the science of vector analysis in three dimensions as recounted in A History of Vector Analysis. Soon after tessarines and coquaternions were introduced as other four-dimensional algebras over R.
One of the first major expositors of the fourth dimension was Charles Howard Hinton, starting in 1880 with his essay What is the Fourth Dimension?; published in the Dublin University magazine.[4] He coined the terms tesseract, ana and kata in his book A New Era of Thought, and introduced a method for visualising the fourth dimension using cubes in the book Fourth Dimension.[5][6] In 1886 Victor Schlegel described[7] his method of visualizing four-dimensional objects with Schlegel diagrams.
In 1908, Hermann Minkowski presented a paper[8] consolidating the role of time as the fourth dimension of spacetime, the basis for Einstein's theories of special and general relativity.[9] But the geometry of spacetime, being non-Euclidean, is profoundly different from that popularised by Hinton. The study of Minkowski space required new mathematics quite different from that of four-dimensional Euclidean space, and so developed along quite different lines. This separation was less clear in the popular imagination, with works of fiction and philosophy blurring the distinction, so in 1973 H. S. M. Coxeter felt compelled to write:
Little, if anything, is gained by representing the fourth Euclidean dimension as time. In fact, this idea, so attractively developed by H. G. Wells in The Time Machine, has led such authors as John William Dunne (An Experiment with Time) into a serious misconception of the theory of Relativity. Minkowski's geometry of space-time is not Euclidean, and consequently has no connection with the present investigation.
— H. S. M. Coxeter, Regular Polytopes[10]
QMRShape notes[edit]
The idea behind shape notes is that the parts of a vocal work can be learned more quickly and easily if the music is printed in shapes that match up with the solfège syllables with which the notes of the musical scale are sung. Forinstance, in the four-shape tradition used in the Sacred Harp and elsewhere, the notes of a C major scale are notated and sung[a] as follows:
The C major scale in shape notes
A skilled singer experienced in a shape note tradition has developed a fluent triple mental association, which links a note of the scale, a shape, and a syllable. This association can be used to help in reading the music. When a song is first sung by a shape note group, they normally sing the syllables (reading them from the shapes) to solidify their command over the notes. Next, they sing the same notes to the words of the music.
The syllables and notes of a shape note system are relative rather than absolute; they depend on the key of the piece. The first note of a major key always has the triangular Fa note, followed (ascending) by Sol, La, etc. The first note of a minor key is always La, followed by Mi, Fa, etc.
The first three notes of (any) major scale – fa, sol, la – are each a tone apart. The fourth to sixth notes are also a tone apart and are also fa, sol, la. The seventh and eighth notes, being separated by a semitone, are indicated mi-fa. This means that just four shapenotes can adequately reflect the "feel" of the whole scale.
Ryan Merkle QMRThe T puzzle is a tiling puzzle consisting of four polygonal shapes which can be put together to form a capital T. The four pieces are usually one isosceles right triangle, two right trapezoids and an irregular shaped pentagon. Despite its apparent simplicity, it is a surprisingly hard puzzle of which the crux is the positioning of the irregular shaped piece. The earliest T puzzles date from around 1900 and were distributed as promotional giveaways. From the 1920s wooden specimen were produced and made available commercially. At 2015, most T puzzles come with a leaflet with additional figures to be constructed. Which shapes can be formed depends on the relative proportions of the different pieces.
The Latin Cross[edit]
The Latin cross puzzle (left) and the T puzzle (right).
The Latin cross puzzle consists of a reassembling a five-piece dissection of the cross with three isosceles right triangles, one right trapezoids and an irregular shaped six-sized piece (see figure). When the pieces of the cross puzzle have the right dimensions, they can also be put together as a rectangle. From Chinese origin, the oldest examples date from the first half of the nineteenth century.[1][2] One of the earliest published descriptions of the puzzle appeared in 1826 in the 'Sequel to the Endless Amusement'.[3] Many other references of the cross puzzle can be found in amusement, puzzle and magicians books throughout the 19th century.[4] The T puzzle is based on the cross puzzle, but without head and has therefore only four pieces. Another difference is that in the dissection of the T, one of the triangles is usually elongated as a right trapezoid. These changes make the puzzle more difficult and clever than the cross puzzle.[5]
Solving the puzzle[edit]
"I know of no polygon-dissection puzzle with as few pieces that is so intractable." – Martin Gardner[6]
With only four pieces, the T puzzle is deceitfully simple. Studies have shown that few people are able solve it under five minutes, with most people needing more than half an hour to solve it.[32] The main difficulty in solving the puzzle is overcoming the functional fixedness of putting the pentagon piece either horizontally or vertically; and related to this, the tendency of trying to fill up the notch of the pentagon. In one study[32] participants were found to spend over 60% of their attempts on such misguided placements of the pentagon piece. And even when the pentagon piece happened to be placed properly, it was mostly not recognized as part of the solution, as a match with the T is not easily seen. The puzzle is easily solved when the insight is reached that the pentagon is part of both the horizontal and vertical stem of the T and that the notch in the pentagon constitutes an inside corner.
QMRSummary[edit]
The following table summarizes each of Chomsky's four types of grammars, the class of language it generates, the type of automaton that recognizes it, and the form its rules must have.
Grammar Languages Automaton Production rules (constraints)
Type-0 Recursively enumerable Turing machine \alpha \rightarrow \beta (no restrictions)
Type-1 Context-sensitive Linear-bounded non-deterministic Turing machine \alpha A \beta \rightarrow \alpha \gamma \beta
Type-2 Context-free Non-deterministic pushdown automaton A \rightarrow \gamma
Type-3 Regular Finite state automaton A \rightarrow a
and
A \rightarrow aB
QMRStoic passions are various forms of emotional suffering in Stoicism, a school of Hellenistic philosophy.
Contents [hide]
1 Relevance
2 Primary passions
3 Subdivisions
3.1 Distress
3.2 Fear
3.3 Lust
3.4 Delight
4 References
5 External links
Relevance[edit]
The passions are transliterated pathê from Greek.[1][2]
Chrysippus thought particularly grief,pleasure, fear and desire were evaluative judgements (according to Groenendijk & de Ruyter - p. 83).[3]
Primary passions[edit]
The Stoics named four primary passions. In On Passions, Andronicus reported the Stoic definitions of these passions (trans. Long & Sedley, pg. 411, modified):
Distress
Distress is an irrational contraction, or a fresh opinion that something bad is present, at which people think it right to be depressed.
Fear
Fear is an irrational aversion, or avoidance of an expected danger.
Lust
Lust is an irrational desire, or pursuit of an expected good.
Delight
Delight is an irrational swelling, or a fresh opinion that something good is present, at which people think it right to be elated.
QMRAccording to Harold Noah (1985), and Farooq Joubish (2009), comparative education has four purposes:
To describe educational systems, processes, or outcomes.
To assist in the development of educational institutions and practices.
To highlight the relationships between education and society.
To establish generalized statements about education that are valid in more than one country.
QMRThe "Instant Insanity" puzzle consists of four cubes with faces colored with four colors (commonly red, blue, green, and white). The objective of the puzzle is to stack these cubes in a column so that each side (front, back, left, and right) of the stack shows each of the four colors. The distribution of colors on each cube is unique.
This problem has a graph-theoretic solution in which a graph with four vertices labeled B, G, R, W (for blue, green, red, and white) can be used to represent each cube; there is an edge between two vertices if the two colors are on the opposite sides of the cube, and a loop at a vertex if the opposite sides have the same color. Trial and error is a slow way to solve this problem, as there are 41,472 arrangements of the four cubes, only one of which is a solution. A generalized version of the puzzle with more than four cubes is NP-complete.[1][2]
The puzzle was created by Franz Owen Armbruster, also known as Frank Armbruster, and published by Parker Brothers in 1967. Over 12 million puzzles were sold. The puzzle is isomorphic to numerous older puzzles, among them the Katzenjammer puzzle,[3][4] patented[5] by Frederick A. Schossow in 1900, and The Great Tantalizer (circa 1940, and the most popular name prior to Instant Insanity).
The puzzle is currently being marketed by Winning Moves.
A Solution to the problem with four cubes[edit]
Given the already colored cubes and the four distinct colors are (Red, Green, Blue, Yellow), we will try to generate a graph which gives a clear picture of all the positions of colors in all the cubes. The resultant graph will contain four vertices one for each color and we will number each edge from one through four (one number for each cube). If an edge connects two vertices (Red and Green) and the number of the edge is three, then it means that the third cube has Red and Green faces opposite to each other.
Image 1 shows four cubes and their colors.
The images are steps to solve the instant insanity problem
Image 2 shows the graph generated by the four cubes.
The images are steps to solve the instant insanity problem
To find a solution to this problem we need the arrangement of four faces of each of the cubes. To represent the information of two opposite faces of all the four cubes we need a directed sub graph. Because two directions can only represent two opposite faces.
So if we have two directed sub graphs, we can actually represent all the four faces (which matter) of all the four cubes.
First directed graph will represent the front and rear faces.
Second directed graph will represent the left and right faces.
We cannot randomly select any two sub graphs - so what is the criteria for selecting?
We need to choose graphs such that:
the two sub graphs have no edges in common, because if there is an edge which is common that means at least one cube has the pair of opposite faces of exactly same color. Meaning: A cube has Red and Blue as front and rear face as well as left and right face.
a sub graph contains only one edge from each cube, because the sub graph has to account for all the cubes and one edge can completely represent a pair of opposite faces.
a sub graph can contain only vertices of degree two, because a degree of two means a color can only be present at faces of two cubes. Easy way to understand is that there are eight faces to be equally divided into four colors. So, two per color.
After understanding these restrictions if we try to derive the two sub graphs, we may end up with one possible set as shown in Image 3. Each edge color represents a cube.
The images are steps to solve the instant insanity problem
From the first sub graph we will derive the front and the rear face colors of the corresponding cube. For e.g.:
The black arrow from Yellow to Blue says that the first cube will have Yellow in the front face and Blue at the Rear.
The blue arrow from Green to Yellow says that the second cube will have Green in the front face and Yellow at the Rear.
The orange arrow from Blue to Red says that the third cube will have Blue in the front face and Red at the Rear.
The purple arrow from Red to Green says that the fourth cube will have Red in the front face and Green at the Rear.
From the second sub graph we will derive the left and the right face colors of the corresponding cube. For e.g.:
The black arrow from Red to Green says that the first cube will have Red in the left face and Green at the Right.
The blue arrow from Blue to Red says that the first cube will have Blue in the left face and Red at the Right.
The orange arrow from Yellow to Blue says that the first cube will have Yellow in the left face and Blue at the Right.
The purple arrow from Green to Yellow says that the first cube will have Green in the left face and Yellow at the Right.
The third image shows the derived stack of cube which is the solution to the problem.
Ryan Merkle QMRCluster of Four Cubes is a 1992 kinetic stainless steel sculpture by George Rickey, installed at the National Gallery of Art Sculpture Garden in Washington, D.C.[1]
Ryan Merkle QMRRay's personal model of reality, called "Time Cube", insists that all of modern physics and education is wrong,[3] arguing among many other things that Greenwich Time is a global conspiracy. He utilized various graphs (along with pictures of Ray) that purport to show how each day is really four separate days—sunup, midday, sundown and midnight (formerly morning, early afternoon, late afternoon and evening)—occurring simultaneously.[2][4]
Ryan Merkle Time Cube was a personal web page operated by self-proclaimed "wisest man on earth" Otis Eugene "Gene" Ray since 1997.[2] It served as a self-publishing outlet for Ray's theory of everything, called "Time Cube", which claims that all current sciences are part of a worldwide conspiracy to teach people lies; the theory's ultimate truth (and what the conspirators are said to be covering up) is that each day actually consists of four days.[3] Alongside these statements Ray described himself as a "godlike" being with superior intelligence who has "absolute" evidence and proof for his views. Academia has not taken Time Cube seriously.[4]
The following quotation from the website illustrates the recurring theme:
When the Sun shines upon Earth, 2 – major Time points are created on opposite sides of Earth – known as Midday and Midnight. Where the 2 major Time forces join, synergy creates 2 new minor Time points we recognize as Sunup and Sundown. The 4-equidistant Time points can be considered as Time Square imprinted upon the circle of Earth. In a single rotation of the Earth sphere, each Time corner point rotates through the other 3-corner Time points, thus creating 16 corners, 96 hours and 4-simultaneous 24-hour Days within a single rotation of Earth – equated to a Higher Order of Life Time Cube.
16 is the squares of the quadrant model
Ryan Merkle QMRThe Soma cube is a solid dissection puzzle invented by Piet Hein in 1933[1] during a lecture on quantum mechanics conducted by Werner Heisenberg. Seven pieces made out of unit cubes must be assembled into a 3×3×3 cube. The pieces can also be used to make a variety of other 3D shapes.
The pieces of the Soma cube consist of all possible combinations of three or four unit cubes, joined at their faces, such that at least one inside corner is formed. There is one combination of three cubes that satisfies this condition, and six combinations of four cubes that satisfy this condition, of which two are mirror images of each other (see Chirality). Thus, 3 + (6 × 4) is 27, which is exactly the number of cells in a 3×3×3 cube.
Ryan Merkle QMRThe Rubik's Revenge (also known as the Master Cube) is a 4×4×4 version of Rubik's Cube. It was released in 1981. Invented by Péter Sebestény, the Rubik's Revenge was nearly called the Sebestény Cube until a somewhat last-minute decision changed the puzzle's name to attract fans of the original Rubik's Cube.[citation needed] Unlike the original puzzle (and the 5×5×5 cube), it has no fixed facets: the centre facets (four per face) are free to move to different positions.
QMRIn geometry, a compound of four tetrahedra can be constructed by four tetrahedra in a number of different symmetry positions.
One compound can be constructed rotating a tetrahedron by 45 degree turns along an axis of the middle of an edge. It has dihedral symmetry, D4 It has the same vertex arrangement as the convex octagonal prism.
Ryan Merkle QMRThe Reuleaux tetrahedron is the intersection of four spheres of radius s centered at the vertices of a regular tetrahedron with side length s. The sphere through each vertex passes through the other three vertices, which also form vertices of the Reuleaux tetrahedron. The Reuleaux tetrahedron has the same face structure as a regular tetrahedron, but with curved faces: four vertices, and four curved faces, connected by six circular-arc edges.
QMrIn geometry, Descartes' theorem states that for every four kissing, or mutually tangent, circles, the radii of the circles satisfy a certain quadratic equation. By solving this equation, one can construct a fourth circle tangent to three given, mutually tangent circles. The theorem is named after René Descartes, who stated it in 1643.
Ryan Merkle QMRCircles of Sustainability is a method for understanding and assessing sustainability, and for managing projects directed towards socially sustainable outcomes.[1] It is intended to handle 'seemingly intractable problems'[2] such as outlined in sustainable development debates. The method is mostly used for cities and urban settlements.
Circles of Sustainability, and its treatment of the social domains of ecology, economics, politics and culture, provides the empirical dimension of an approach called 'engaged theory'. Developing Circles of Sustainability is part of larger project called 'Circles of Social Life', using the same four-domain model to analyze questions of resilience, adaptation, security, reconciliation. It is also being used in relation to thematics such as 'Circles of Child Wellbeing' (with World Vision).
The rationale for this new method is clear. As evidenced by Rio+20 and the UN Habitat World Urban Forum in Napoli (2012) and Medellin (2014), sustainability assessment is on the global agenda.[3] However, the more complex the problems, the less useful current sustainability assessment tools seem to be for assessing across different domains: economics, ecology, politics and culture.[4] For example, the Triple Bottom Line approach tends to take the economy as its primary point of focus with the domain of the environmental as the key externality. Secondly, the one-dimensional quantitative basis of many such methods means that they have limited purchase on complex qualitative issues. Thirdly, the size, scope and sheer number of indicators included within many such methods means that they are often unwieldy and resist effective implementation. Fourthly, the restricted focus of current indicator sets means that they do not work across different organizational and social settings—corporations and other institutions, cities, and communities.[5] Most indicator approaches, such as the Global Reporting Initiative or ISO14031, have been limited to large corporate organizations with easily definable legal and economic boundaries. Circles of Sustainability was developed to respond to those limitations
Ryan Merkle QMRIn geometry, Villarceau circles /viːlɑːrˈsoʊ/ are a pair of circles produced by cutting a torus obliquely through the center at a special angle. Given an arbitrary point on a torus, four circles can be drawn through it. One is in the plane (containing the point) parallel to the equatorial plane of the torus. Another is perpendicular to it. The other two are Villarceau circles. They are named after the French astronomer and mathematician Yvon Villarceau (1813–1883). Mannheim (1903) showed that the Villarceau circles meet all of the parallel circular cross-sections of the torus at the same angle, a result that he said a Colonel Schoelcher had presented at a congress in 1891.
Ryan Merkle QMRFigure 2: Four complementary pairs of solutions to Apollonius' problem; the given circles are black.
Ryan Merkle In Euclidean plane geometry, Apollonius's problem is to construct circles that are tangent to three given circles in a plane (Figure 1). Apollonius of Perga (ca. 262 BC – ca. 190 BC) posed and solved this famous problem in his work Ἐπαφαί (Epaphaí, "Tangencies"); this work has been lost, but a 4th-century report of his results by Pappus of Alexandria has survived. Three given circles generically have eight different circles that are tangent to them (Figure 2) and each solution circle encloses or excludes the three given circles in a different way: in each solution, a different subset of the three circles is enclosed (its complement is excluded) and there are 8 subsets of a set whose cardinality is 3, since 8 = 23.
There are four solutions
Ryan Merkle QMrFour Sided Triangle is a 1953 British science-fiction film directed by Terence Fisher, adapted from a novel by William F. Temple. It starred Stephen Murray, Barbara Payton and James Hayter. It was produced by Hammer Film Productions at Bray Studios.
The film dealt with the moral and scientific themes (not to mention "mad lab" scenes) that were soon to put Hammer Films on the map with the same director's The Curse of Frankenstein. Four Sided Triangle has most in common with Fisher's Frankenstein Created Woman (1967).
Ryan Merkle QMRIn geometry, an orthocentric system is a set of four points on a plane, one of which is the orthocenter of the triangle formed by the other three.
If four points form an orthocentric system, then each of the four points is the orthocenter of the other three. These four possible triangles will all have the same nine-point circle. Consequently these four possible triangles must all have circumcircles with the same circumradius.
Further properties[edit]
The four Euler lines of an orthocentric system are orthogonal to the four orthic axes of an orthocentric system.
The six connectors that join any pair of the original four orthocentric points will produce pairs of connectors that are orthogonal to each other such that they satisfy the distance equations
AB^2 + CH^2 = AC^2 + BH^2 = BC^2 + AH^2 = 4R^2
where R is the common circumradius of the four possible triangles. These equations together with the law of sines result in the identity
\frac{BC}{\sin{A}} = \frac{AC}{\sin{B}} = \frac{AB}{\sin{C}} = \frac{HA}{|\cos{A}|} = \frac{HB}{|\cos{B}|} = \frac{HC}{|\cos{C}|} = 2R.
Feuerbach's theorem states that the nine-point circle is tangent to the incircle and the three excircles of a reference triangle. Because the nine-point circle is common to all four possible triangles in an orthocentric system it is tangent to 16 circles comprising the incircles and excircles of the four possible triangles.
Any conic that passes through the four orthocentric points can only be a rectangular hyperbola. This is a result of Feuerbach's conic theorem that states that for all circumconics of a reference triangle that also passes through its orthocenter, the locus of the center of such circumconics form the nine-point circle and that the circumconics can only be rectangular hyperbolas.
Note that the locus of the perspectors of this family of rectangular hyperbolas will always lie on the four orthic axes. So if a rectangular hyperbola is drawn through four orthocentric points it will have one fixed center on the common nine-point circle but it will have four perspectors one on each of the orthic axes of the four possible triangles. Note also that the one point on the nine-point circle that is the center of this rectangular hyperbola will have four different definitions dependent on which of the four possible triangles is used as the reference triangle.
The well documented rectangular hyperbolas that pass through four orthocentric points are the Feuerbach, Jeřábek and Kiepert circumhyperbolas of the reference triangle ABC in a normalized system with H as the orthocenter.
The four possible triangles have a set of four inconics known as the orthic inconics that share certain properties. The contacts of these inconics with the four possible triangles occur at the vertices of their common orthic triangle. In a normalized orthocentric system the orthic inconic that is tangent to the sides of the triangle ABC is an inellipse and the orthic inconics of the other three possible triangles are hyperbolas. These four orthic inconics also share the same Brianchon point, H, the orthocentric point closest to the common nine-point center. The centers of these orthic inconics are the symmedian points, K of the four possible triangles.
There are many documented cubics that pass through a reference triangle and its orthocenter. The circumcubic known as the orthocubic - K006 is interesting in that it passes through three orthocentric systems as well as the three vertices of the orthic triangle (but not the orthocenter of the orthic triangle). The three orthocentric systems are the incenter and excenters, the reference triangle and its orthocenter and finally the orthocenter of the reference triangle together with the three other intersection points that this cubic has with the circumcircle of the reference triangle.
Any two polar circles of two triangles in an orthocentric system are orthogonal.[2]:p. 177
Ryan Merkle QMrMitsunobu Matsuyama's "Paradox" uses four congruent quadrilaterals and a small square, which form a larger square. When the quadrilaterals are rotated about their centers they fill the space of the small square, although the total area of the figure seems unchanged. The apparent paradox is explained by the fact that the side of the new large square is a little smaller than the original one. If a is the side of the large square and θ is the angle between two opposing sides in each quadrilateral, then the quotient between the two areas is given by sec2θ − 1. For θ = 5°, this is approximately 1.00765, which corresponds to a difference of about 0.8%.
Ryan Merkle The missing square puzzle is an optical illusion used in mathematics classes to help students reason about geometrical figures, or rather to teach them to not reason using figures, but only using the textual description thereof and the axioms of geometry. It depicts two arrangements made of similar shapes in slightly different configurations. Each apparently forms a 13×5 right-angled triangle, but one has a 1×1 hole in it.
It has four colors
Ryan Merkle QMRThe medial triangle or midpoint triangle of a triangle ABC is the triangle with vertices at the midpoints of the triangle's sides AB, AC and BC. It is the n=3 case of the midpoint polygon of a polygon with n sides. The medial triangle is not the same thing as the median triangle, which is the triangle whose sides have the same lengths as the medians of ABC.
Contents [hide]
1 Properties
2 Coordinates
3 Anticomplementary triangle
4 References
5 External links
Properties[edit]
The medial triangle can also be viewed as the image of triangle ABC transformed by a homothety centered at the centroid with ratio -1/2. Hence, the medial triangle is inversely similar and shares the same centroid and medians with triangle ABC. It also follows from this that the perimeter of the medial triangle equals the semiperimeter of triangle ABC, and that the area is one quarter of the area of triangle ABC. Furthermore, the four triangles that the original triangle is subdivided into by the medial triangle are all mutually congruent by SSS, so their areas are equal and thus the area of each is 1/4 the area of the original triangle.[1]:p.177
Ryan Merkle QMRIn February 2004 then Federal Communications Commission Chairman Michael Powell announced a set of non-discrimination principles, which he called the principles of "Network Freedom". In a speech at the Silicon Flatirons Symposium, Powell encouraged ISPs to offer users these four freedoms:
Freedom to access content.
Freedom to run applications.
Freedom to attach devices.
Freedom to obtain service plan information.[21]
Ryan Merkle QMRDuring the FCC's hearing, the National Cable & Telecommunications Association urged the FCC to adopt the four criteria laid out in its 2005 Internet Policy Statement as the requisite openness. This made up a voluntary set of four net neutrality principles.[24] Implementation of the principles was not mandatory; that would require an FCC rule or federal law.[25] The modified principles were as follows:[26][27]
Consumers are entitled to access the lawful Internet content of their choice;
Consumers are entitled to run applications and services of their choice, subject to the needs of law enforcement;
Consumers are entitled to connect their choice of legal devices that do not harm the network; and
Consumers are entitled to competition among network providers, application and service providers, and content providers.
QMRThe Internet protocol suite is the computer networking model and set of communications protocols used on the Internet and similar computer networks. It is commonly known as TCP/IP, because its most important protocols, the Transmission Control Protocol (TCP) and the Internet Protocol (IP) were the first networking protocols defined in this standard. It is occasionally known as the DoD model, because the development of the networking model was funded by DARPA, an agency of the United States Department of Defense.
TCP/IP provides end-to-end connectivity specifying how data should be packetized, addressed, transmitted, routed and received at the destination. This functionality is organized into four abstraction layers which are used to sort all related protocols according to the scope of networking involved.[1][2] From lowest to highest, the layers are the link layer, containing communication methods for data that remains within a single network segment (link); the internet layer, connecting independent networks, thus establishing internetworking; the transport layer handling host-to-host communication; and the application layer, which provides process-to-process data exchange for applications.
The TCP/IP model and many of its protocols are maintained by the Internet Engineering Task Force (IETF).
Ryan Merkle QMR4G, short for fourth generation, is the fourth generation of mobile telecommunications technology, succeeding 3G. A 4G system must provide capabilities defined by ITU in IMT Advanced. Potential and current applications include amended mobile web access, IP telephony, gaming services, high-definition mobile TV, video conferencing, 3D television, and cloud computing.[citation needed]
Ryan Merkle QMRThe four Network Access Points (NAPs) were defined under the U.S. National Information Infrastructure (NII) document as transitional data communications facilities at which Network Service Providers (NSPs) would exchange traffic, in replacement of the publicly financed NSFNET Internet backbone.[1] The National Science Foundation let contracts supporting the four NAPs, one to MFS Datanet for the preexisting MAE-East in Washington, D.C., and three others to Sprint, Ameritech, and Pacific Bell, for new facilities of various designs and technologies, in New York (actually Pennsauken, New Jersey), Chicago, and California, respectively.[2] As a transitional strategy, they were effective, giving commercial network operators a bridge from the Internet's beginnings as a government-funded academic experiment, to the modern Internet of many private-sector competitors collaborating to form a network-of-networks, anchored around Internet Exchange Points.
This was particularly timely, coming hard on the heels of the ANS CO+RE controversy,[3][4] which had disturbed the nascent industry, led to congressional hearings,[5] resulted in a law allowing NSF to promote and use networks that carry commercial traffic,[6] prompted a review of the administration of NSFNET by the NSF's Inspector General (no serious problems were found),[7] and caused commercial operators to realize that they needed to be able to communicate with each other independent of third parties or at neutral exchange points.
Today, the phrase "Network Access Point" is of historical interest only, since the four transitional NAPs disappeared long ago, replaced by modern IXPs, though in Spanish-speaking Latin America, the phrase lives on to a small degree, among those who conflate the NAPs with Internet Exchange Points (IXPs).
Ryan Merkle QMrInternet Protocol version 4 (IPv4) is the fourth version of the Internet Protocol (IP). It is one of the core protocols of standards-based internetworking methods in the Internet, and was the first version deployed for production in the ARPANET in 1983. It still routes most Internet traffic today,[1] despite the ongoing deployment of a successor protocol, IPv6. IPv4 is described in IETF publication RFC 791 (September 1981), replacing an earlier definition (RFC 760, January 1980).
QMRThe Four Horsemen of the Infocalypse is a term for internet criminals, or the imagery of internet criminals.
A play on Four Horsemen of the Apocalypse, it refers to types of criminals who use the internet to facilitate crime and consequently jeopardize the rights of honest internet users. There does not appear to be an exact definition for who the Horsemen are, but they are usually described as terrorists, drug dealers, pedophiles, and organized crime. Other sources use slightly different descriptions but generally refer to the same types of criminals. The term was coined by Timothy C. May in 1988, who referred to them as "child pornographers, terrorists, drug dealers, etc."[1] when discussing the reasons for limited civilian use of cryptography tools. Among the most famous of these is in the Cypherpunk FAQ,[2] which states:
8.3.4. "How will privacy and anonymity be attacked?"
[...]
like so many other "computer hacker" items, as a tool for the "Four Horsemen": drug-dealers, money-launderers, terrorists, and pedophiles.
17.5.7. "What limits on the Net are being proposed?"
[...]
Newspapers are complaining about the Four Horsemen of the Infocalypse:
terrorists, pedophiles, drug dealers, and money launderers
The term seems to be used less often in discussions about online criminal activity, but more often in discussions about the negative, or chilling effects such activity has had on regular users' daily experiences online. It is also used frequently to describe the political tactic "Think of the children". A message from the same mailing list states:[3]
How to get what you want in 4 easy stages:
Have a target "thing" you wish to stop, yet lack any moral, or practical reasons for doing so?
Pick a fear common to lots of people, something that will evoke a gut reaction: terrorists, pedophiles, serial killers.
Scream loudly to the media that "thing" is being used by perpetrators. (Don't worry if this is true, or common to all other things, or less common with "thing" than with other long established systems—payphones, paper mail, private hotel rooms, lack of bugs in all houses etc.)
Say that the only way to stop perpetrators is to close down "thing", or to regulate it to death, or to have laws forcing en-mass tapability of all private communications on "thing". Don't worry if communicating on "thing" is a constitutionally protected right, if you have done a good job in choosing and publicising the horsemen in 2, no one will notice, they will be too busy clamouring for you to save them from the supposed evils.
The four supposed threats may be used all at once or individually, depending on the circumstances:[4]
Ryan Merkle QMRLight's early work focused on the nature of interaction between persons who use AAC and their communication partners,[7] and resulted in her proposal of a definition for communicative competence in AAC,[8] including four social purposes of communicative interaction in AAC: the expression of needs and wants to a listener, the transfer of information as in more general conversation, the development of social closeness through such things as jokes and cheering, and finally social etiquette practices such as "please" and "thank you". These four purposes vary in terms of the relative importance of the content, rate, duration and the focus of the interaction. It is important that the AAC systems selected also reflect the priorities of the individual and their family.
Ryan Merkle QMRLight's early work focused on the nature of interaction between persons who use AAC and their communication partners,[7] and resulted in her proposal of a definition for communicative competence in AAC,[8] including four social purposes of communicative interaction in AAC: the expression of needs and wants to a listener, the transfer of information as in more general conversation, the development of social closeness through such things as jokes and cheering, and finally social etiquette practices such as "please" and "thank you". These four purposes vary in terms of the relative importance of the content, rate, duration and the focus of the interaction. It is important that the AAC systems selected also reflect the priorities of the individual and their family.
Ryan Merkle QMRThe first formal definition of free software was published by FSF in February 1986.[17] That definition, written by Richard Stallman, is still maintained today and states that software is free software if people who receive a copy of the software have the following four freedoms.[18][19] The numbering begins with zero, not only as a spoof on the common usage of zero-based numbering in programming languages, but also because "Freedom 0" was not initially included in the list, but later added first in the list as it is was considered very important.
Freedom 0: The freedom to run the program for any purpose.
Freedom 1: The freedom to study how the program works, and change it to make it do what you wish.
Freedom 2: The freedom to redistribute copies so you can help your neighbor.
Freedom 3: The freedom to improve the program, and release your improvements (and modified versions in general) to the public, so that the whole community benefits.
Ryan Merkle QMRLife-cycle assessment (LCA, also known as life-cycle analysis, ecobalance, and cradle-to-grave analysis)[1] is a technique to assess environmental impacts associated with all the stages of a product's life from cradle to grave (i.e., from raw material extraction through materials processing, manufacture, distribution, use, repair and maintenance, and disposal or recycling). LCAs can help avoid a narrow outlook on environmental concerns by:
Four main phases[edit]
Illustration of LCA phases
According to the ISO 14040[8] and 14044[9] standards, a Life Cycle Assessment is carried out in four distinct phases as illustrated in the figure shown to the right. The phases are often interdependent in that the results of one phase will inform how other phases are completed.
Goal and scope[edit]
An LCA starts with an explicit statement of the goal and scope of the study, which sets out the context of the study and explains how and to whom the results are to be communicated. This is a key step and the ISO standards require that the goal and scope of an LCA be clearly defined and consistent with the intended application. The goal and scope document therefore includes technical details that guide subsequent work:
the functional unit, which defines what precisely is being studied and quantifies the service delivered by the product system, providing a reference to which the inputs and outputs can be related. Further, the functional unit is an important basis that enables alternative goods, or services, to be compared and analyzed.[10]
the system boundaries;
any assumptions and limitations;
the allocation methods used to partition the environmental load of a process when several products or functions share the same process; and
the impact categories chosen.
Life cycle inventory[edit]
This is an example of a Life-cycle inventory (LCI) diagram
Life Cycle Inventory (LCI) analysis involves creating an inventory of flows from and to nature for a product system. Inventory flows include inputs of water, energy, and raw materials, and releases to air, land, and water. To develop the inventory, a flow model of the technical system is constructed using data on inputs and outputs. The flow model is typically illustrated with a flow chart that includes the activities that are going to be assessed in the relevant supply chain and gives a clear picture of the technical system boundaries. The input and output data needed for the construction of the model are collected for all activities within the system boundary, including from the supply chain (referred to as inputs from the techno-sphere).
The data must be related to the functional unit defined in the goal and scope definition. Data can be presented in tables and some interpretations can be made already at this stage. The results of the inventory is an LCI which provides information about all inputs and outputs in the form of elementary flow to and from the environment from all the unit processes involved in the study.
Inventory flows can number in the hundreds depending on the system boundary. For product LCAs at either the generic (i.e., representative industry averages) or brand-specific level, that data is typically collected through survey questionnaires. At an industry level, care has to be taken to ensure that questionnaires are completed by a representative sample of producers, leaning toward neither the best nor the worst, and fully representing any regional differences due to energy use, material sourcing or other factors. The questionnaires cover the full range of inputs and outputs, typically aiming to account for 99% of the mass of a product, 99% of the energy used in its production and any environmentally sensitive flows, even if they fall within the 1% level of inputs.
One area where data access is likely to be difficult is flows from the techno-sphere. The technosphere is more simply defined as the man-made world. Considered by geologists as secondary resources, these resources are in theory 100% recyclable; however, in a practical sense the primary goal is salvage.[11] For an LCI, these technosphere products (supply chain products) are those that have been produced by man and unfortunately those completing a questionnaire about a process which uses man-made product as a means to an end will be unable to specify how much of a given input they use. Typically, they will not have access to data concerning inputs and outputs for previous production processes of the product. The entity undertaking the LCA must then turn to secondary sources if it does not already have that data from its own previous studies. National databases or data sets that come with LCA-practitioner tools, or that can be readily accessed, are the usual sources for that information. Care must then be taken to ensure that the secondary data source properly reflects regional or national conditions.
Life cycle impact assessment[edit]
Inventory analysis is followed by impact assessment. This phase of LCA is aimed at evaluating the significance of potential environmental impacts based on the LCI flow results. Classical life cycle impact assessment (LCIA) consists of the following mandatory elements:
selection of impact categories, category indicators, and characterization models;
the classification stage, where the inventory parameters are sorted and assigned to specific impact categories; and
impact measurement, where the categorized LCI flows are characterized, using one of many possible LCIA methodologies, into common equivalence units that are then summed to provide an overall impact category total.
In many LCAs, characterization concludes the LCIA analysis; this is also the last compulsory stage according to ISO 14044:2006. However, in addition to the above mandatory LCIA steps, other optional LCIA elements – normalization, grouping, and weighting – may be conducted depending on the goal and scope of the LCA study. In normalization, the results of the impact categories from the study are usually compared with the total impacts in the region of interest, the U.S. for example. Grouping consists of sorting and possibly ranking the impact categories. During weighting, the different environmental impacts are weighted relative to each other so that they can then be summed to get a single number for the total environmental impact. ISO 14044:2006 generally advises against weighting, stating that “weighting, shall not be used in LCA studies intended to be used in comparative assertions intended to be disclosed to the public”. This advice is often ignored, resulting in comparisons that can reflect a high degree of subjectivity as a result of weighting.[citation needed]
Interpretation[edit]
Life Cycle Interpretation is a systematic technique to identify, quantify, check, and evaluate information from the results of the life cycle inventory and/or the life cycle impact assessment. The results from the inventory analysis and impact assessment are summarized during the interpretation phase. The outcome of the interpretation phase is a set of conclusions and recommendations for the study. According to ISO 14040:2006, the interpretation should include:
identification of significant issues based on the results of the LCI and LCIA phases of an LCA;
evaluation of the study considering completeness, sensitivity and consistency checks; and
conclusions, limitations and recommendations.
A key purpose of performing life cycle interpretation is to determine the level of confidence in the final results and communicate them in a fair, complete, and accurate manner. Interpreting the results of an LCA is not as simple as "3 is better than 2, therefore Alternative A is the best choice"! Interpreting the results of an LCA starts with understanding the accuracy of the results, and ensuring they meet the goal of the study. This is accomplished by identifying the data elements that contribute significantly to each impact category, evaluating the sensitivity of these significant data elements, assessing the completeness and consistency of the study, and drawing conclusions and recommendations based on a clear understanding of how the LCA was conducted and the results were developed.
QMrDECA is divided into four divisions: High School, Collegiate DECA, Alumni, and Professional
QMRThe Bewcastle Cross is an Anglo-Saxon cross which is still in its original position within the churchyard of St Cuthbert's church at Bewcastle, in the English county of Cumbria. The cross, which probably dates from the 7th or early 8th century, features reliefs and inscriptions in the runic alphabet. The head of the cross is missing but the remains are 14.5 feet (4.4 metres) high, and almost square in section 22 x 21 1/4 inches (56 x 54 cm) at the base. The crosses of Bewcastle and Ruthwell have been described by the scholar Nikolaus Pevsner as "the greatest achievement of their date in the whole of Europe".[1]
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