formulasearchengine - User contributions [en]

Adjacency matrix

2015-01-13T09:57:39Z

140.113.136.218: /* Properties */

It is time to address the slow computer issues whether or not we never learn how. Just considering the computer is working thus slow or keeps freezing up; does not signify to not address the issue and fix it. You may or can not be aware which any computer owner must know which there are certain points which the computer needs to keep the best performance. The sad truth is the fact that a lot of folks who own a program have no idea that it needs routine maintenance just like their vehicles. But registry is conveniently corrupted and damaged whenever you may be using the computer. Overtime, without proper repair, it can be loaded with mistakes plus incorrect or missing information which may create a program unable to function properly or implement a certain task. And whenever your system cannot find the correct information, it may not understand what to do. Then it freezes up! That is the real cause of your trouble. With the Internet, the risk to your registry is more and windows XP error messages may appear frequently. Why? The malicious wares like viruses, Trojans, spy-wares, ad wares, and the like gets recorded too. Cookies are best examples. You reach save passwords, and stuff, proper? That is a easy example of the register functioning. Analysis a files plus clean it up regularly. Destroy all unwanted plus unused files because they just jam the computer program. It usually definitely improve the speed of the computer plus be careful that the computer do not infected by a virus. Remember always to update the antivirus software every time. If you never utilize your computer pretty frequently, you are able to take a free antivirus. Use a [http://bestregistrycleanerfix.com/registry-reviver registry reviver]. This usually look your Windows registry for 3 types of keys that will really hurt PC performance. These are: duplicate, missing, plus corrupted. S/w connected error handling - If the blue screen bodily memory dump happens following the installation of s/w application or perhaps a driver it may be which there is system incompatibility. By booting into secure mode and removing the software you are able to immediately fix this error. We may also try out a "program restore" to revert to an earlier state. To accelerate a computer, we merely have to be able to do away with all these junk files, allowing a computer to locate what it wants, when it wants. Luckily, there's a tool which enables you to do this easily and rapidly. It's a tool called a 'registry cleaner'. A registry cleaner is a system which cleans the registry. The Windows registry always gets flooded with junk data, info that has not been removed from uninstalled programs, erroneous file organization and different computer-misplaced entries. These clean little program software tools are quite well-known nowadays and you will find very a few good ones found on the Internet. The wise ones provide you choice to maintain, clean, update, backup, plus scan the System Registry. Whenever it finds supposedly unwanted ingredients inside it, the registry cleaner lists them plus recommends the user to delete or repair these orphaned entries and corrupt keys.

Statistical coupling analysis

2014-07-04T05:44:56Z

140.113.15.171: /* Definition of statistical coupling energy */

I lately had the chance to test a plugin called the WooCommerce Reserving and Appointments Plugin from Tyche Softwares. It adds reserving and appointment functionality to your WordPress powered web site, and integrates properly with WooCommerce to charge a payment for these bookings. 

I’ll use my own area aboutblankenspoor.nl for this. It runs on a VPS with 2GB of memory, and a pair of CPU cores totalling four.6GHz. It’s effectively suited to the job, and it has Installatron to install both Magento and WordPress. What you do see is a convenient dashboard, with your latest sales information, search terms, bestsellers etc. This can be very motivating when orders begin rolling in. Including a product gives you some more customization options. As with Magento you'll be able to add simple products, grouped merchandise and configurable products (referred to as variable products). There's also an possibility so as to add an affiliate product of an external vendor (extra on this later). If variable products cannot be added to the cart, delete /woocommerce/single-product/add-to-cart/variable.php from your theme’s directory and ask your [http://Www.squidoo.com/search/results?q=theme+supplier theme supplier] to update their [http://bestwoocommercethemes.blogspot.co.uk/2014/05/the-ultimate-top-5-responsive-themes.html WooCommerce templates] Whether you're working a superstore selling thousands of merchandise, or a just a sole dealer selling handcrafted arts and crafts WooCommerce has you covered. So, within the unfortunate event that your WordPress web site gets hacked, your entire delicate and important e-commerce data like customer accounts, orders, products definitions, and digital merchandise are all nonetheless secure in the cloud and by no means uncovered to the hacker Merely restore your WordPress website and you’re back in enterprise. Why we developed Cart66 Cloud Moreover, over the past few weeks of testing, we corresponded with the developer to make some suggestions, and several of these recommendations have been carried out in the current version of the plugin. These items make the plugin extra usable for nonprofits, and we predict you’ll perceive why once you see the video. More Particulars on the [http://www.wikipedia.org/wiki/Booking Booking] and Appointments Plugin Whether or not you are operating a superstore selling hundreds of products, or a just a sole dealer selling handcrafted arts and crafts WooCommerce has you coated. You can read all about WooCommerce' features on the WooCommerce web site Narrowing down your decisions for the correct ecommerce solution is essential. While you’ve narrowed the selection right down to Zen Cart or Woo Commerce, it's essential choose the appropriate one to your particular wants. These are both great selections, but the WordPress person may have a harder resolution since Woo Commerce works with WordPress. I wanted to do a write up on this site as a result of the booking functionality for WordPress is a growing phase of the industry. As increasingly more people choose to start their very own companies this functionality will turn out to be useful for sole proprietors, small nonprofits, and different unbiased contractors like coaches, consultants, and attorneys, among others. Blaszok is a fantastic, simple to use & fully customi zable theme As you may see by the previews (home design types & examples) t his theme could also be used for nearly any web site I hope that you'll find as a lot enjoyable utilizing Blaszok as we had making it. We're totally dedicated to this project and we would like to develop it further but for that we want your support. EDEN is a retina multi-purpose WordPress theme with a ship-load of wonderful features, like customizable headers, video backgrounds, Qode slider and far much more. Nice for a company or private blog.

Trilinear interpolation

2012-07-06T15:55:25Z

140.113.47.171: /* Method */ explain V[x,y,z]

Human being who wrote the short post is [http://Www.ehow.com/search.html?s=called+Roberto called Roberto] Ledbetter and his wife doesn't like it at all. In his professional life he typically is a people manager. He's always [https://Www.gov.uk/search?q=loved+living loved living] inside Guam and he has everything that he prerequisites there. The preference hobby for him and / or his kids is farming but he's been removing on new things these days. He's been working on the length of his website for some era now. Check it available here: http://circuspartypanama.com my site :: [http://circuspartypanama.com clash of clans hack no survey no password]

Method of averaging

2011-09-16T03:44:07Z

140.113.156.133:

[[File:GQ(2,2), the Doily.svg|thumb|GQ(2,2), the Doily]]

In [[geometry]], a '''generalized quadrangle''' is an [[incidence structure]] whose main feature is the lack of any triangles (yet containing many quadrangles). A generalized quadrangle is by definition a [[polar space]] of rank two. They are the {{nowrap|[[generalized n-gon]]s}} with ''n'' = 4. They are also precisely the [[Partial geometry|partial geometries]] pg(''s'',''t'',α) with α = 1.

==Definition==

A generalized quadrangle is an incidence structure (''P'',''B'',I), with I ⊆ ''P'' × ''B'' an [[incidence relation]], satisfying certain [[axiom]]s. Elements of ''P'' are by definition the ''points'' of the generalized quadrangle, elements of ''B'' the ''lines''. The axioms are the following:
* There is an ''s'' (''s'' ≥ 1) such that on every line there are exactly ''s'' + 1 points. There is at most one point on two distinct lines.
* There is a ''t'' (''t'' ≥ 1) such that through every point there are exactly ''t'' + 1 lines. There is at most one line through two distinct points.
* For every point ''p'' not on a line ''L'', there is a unique line ''M'' and a unique point ''q'', such that ''p'' is on ''M'', and ''q'' on ''M'' and ''L''.

(''s'',''t'') are the ''parameters'' of the generalized quadrangle. The parameters are allowed to be infinite. If either ''s'' or ''t'' is one, the generalized quadrangle is called ''trivial''. A generalized quadrangle with parameters (''s'',''t'') is often denoted by GQ(''s'',''t'').

The smallest non-trivial generalized quadrangle is GQ(2,2), whose representation has been dubbed "the doily" by Stan Payne in 1973.

==Properties==

* <math>|P|=(s t+1)(s+1)</math>
* <math>|B|=(s t+1)(t+1)</math>
* <math>(s+t)|st(s+1)(t+1)</math>
* <math>s\neq 1 \Longrightarrow t\leq s^2</math>
* <math>t\neq 1 \Longrightarrow s\leq t^2</math>

==Graphs==
[[File:GQ24.svg|250px|right|thumb| [[Line graph]] of '''generalized quadrangle''' {{nowrap|GQ(2,4)}}]]

There are two interesting graphs that can be obtained from a generalized quadrangle.
* The ''collinearity graph'' having as vertices the points of a generalized quadrangle, with the collinear points connected. This graph is a [[strongly regular graph]].
* The ''incidence graph'' whose vertices are the points and lines of the generalized quadrangle and two vertices are adjacent if one is a point, the other a line and the point lies on the line. The incidence graph of a generalized quadrangle is characterized by being a [[Connected graph|connected]], [[bipartite graph]] with [[diameter (graph theory)|diameter]] four and [[girth (graph theory)|girth]] eight. Incidence graphs of configurations are today generally called [[Levi graph]]s, but the original Levi graph was the incidence graph of the GQ(2,2).

==Duality==

If (''P'',''B'',I) is a generalized quadrangle with parameters (''s'',''t''), then (''B'',''P'',I-1), with I-1 the inverse incidence relation, is also a generalized quadrangle. This is the ''dual generalized quadrangle''. Its parameters are (''t'',''s''). Even if ''s'' = ''t'', the dual structure need not be isomorphic with the original structure.

==Classical generalized quadrangles==
When looking at the different cases for [[polar space]]s of rank at least three, and extrapolating them to rank 2, one finds these (finite) generalized quadrangles :

* A hyperbolic [[quadric]] <math>Q^+(3,q)</math>, a parabolic quadric <math>Q(4,q)</math> and an elliptic quadric <math>Q^-(5,q)</math> are the only possible quadrics in projective spaces over finite fields with projective index 1. We find these parameters respectively :
: <math>Q(3,q) :\ s=q,t=1</math> (this is just a grid)
: <math>Q(4,q) :\ s=q,t=q</math>
: <math>Q(5,q) :\ s=q,t=q^2</math>
* A hermitian variety <math>H(n,q^2)</math> has projective index 1 if and only if n is 3 or 4. We find :
: <math> H(3,q^2) :\ s=q^2,t=q</math>
: <math>H(4,q^2) :\ s=q^2,t=q^3</math>
* A symplectic polarity in <math>PG(2d+1,q)</math> has a maximal isotropic subspace of dimension 1 if and only if <math>d=1</math>. Here, we find a generalized quadrangle <math>W(3,q)</math>, with <math>s=q,t=q</math>.

The generalized quadrangle derived from <math>Q(4,q)</math> is always isomorphic with the dual of <math>W(3,q)</math>, and they are both self-dual and thus isomorphic to each other if and only if <math>q</math> is even.

==Non-classical examples==

* Let ''O'' be a [[hyperoval]] in <math>PG(2,q)</math> with ''q'' an even [[prime power]], and embed that projective (desarguesian) plane <math>\pi</math> into <math>PG(3,q)</math>. Now consider the incidence structure <math>T_2^{*}(O)</math> where the points are all points not in <math>\pi</math>, the lines are those not on <math>\pi</math>, intersecting <math>\pi</math> in a point of ''O'', and the incidence is the natural one. This is a ''(q-1,q+1)''-generalized quadrangle.
* Let ''q'' be a [[prime power]] (odd or even) and consider a symplectic polarity <math>\theta</math> in <math>PG(3,q)</math>. Choose a random point ''p'' and define <math>\pi=p^{\theta}</math>. Let the lines of our incidence structure be all absolute lines not on <math>\pi</math> together with all lines through ''p'' which are not on <math>\pi</math>, and let the points be all points of <math>PG(3,q)</math> except those in <math>\pi</math>. The incidence is again the natural one. We obtain once again a ''(q-1,q+1)''-generalized quadrangle

==Restrictions on parameters==

By using grids and dual grids, any [[integer]] ''z'', ''z'' ≥ 1 allows generalized quadrangles with parameters (1,''z'') and (''z'',1). Apart from that, only the following parameters have been found possible until now, with ''q'' an arbitrary [[prime power]] :

: <math> (q,q)</math>
: <math> (q,q^2)</math> and <math> (q^2,q)</math>
: <math> (q^2,q^3)</math> and <math> (q^3,q^2)</math>
: <math> (q-1,q+1)</math> and <math> (q+1,q-1)</math>

==References==
* [[S. E. Payne]] and [[J. A. Thas]]. Finite generalized quadrangles. Research Notes in Mathematics, 110. Pitman (Advanced Publishing Program), Boston, MA, 1984. vi+312 pp. ISBN 0-273-08655-3
* [[Koen Thas]]. Symmetry in finite generalized quadrangles. Frontiers in Mathematics. Birkhäuser Verlag, Basel, 2004. xxii+214 pp. ISBN 3-7643-6158-1

[[Category:Incidence geometry]]
[[Category:Set families]]

Butson-type Hadamard matrix

2010-01-01T13:58:45Z

140.113.13.71: /* Examples */

'''Roundness''' is the measure of how closely the shape of an object approaches that of a [[circle]].

Roundness is dominated by the shape's large-scale features rather than the sharpness of its edges and corners, or the [[surface roughness]] of a manufactured object. A smooth [[ellipse]] can have low roundness, if its [[eccentricity (mathematics)|eccentricity]] is large. [[Regular polygon]]s increase their roundness with increasing numbers of sides, even though they are still sharp-edged.

Roundness applies in two dimensions. Its analogue in three dimensions is [[sphericity]]. In [[geology]] and the study of [[sediment]]s (where three dimensional particles are most important), [[roundness (geology)|roundness]] is considered to be the measurement of surface roughness and the overall shape is described by sphericity.

== Simple definitions ==
The [[ISO]] definition of roundness is based on the ratio between the [[inscribed circle|inscribed]] and the [[circumscribed circle]]s, i.e. the maximum and minimum sizes for circles that are just sufficient to fit inside and to enclose the shape.<ref>[[ISO]] 1101</ref><ref>{{Cite web
|title=Introduction to the Measurement of Roundness
|publisher=[[Taylor-Hobson]] Precision
|quote=the separation of two concentric circles that just enclose the circular section of interest.
|url=http://www.rank-instrument.com/download/Introduction%20to%20the%20Measurement%20of%20Roundness.pdf
}}</ref>

=== Diameter ===
Having a constant [[diameter]], measured at varying angles around the shape, is often considered to be a simple measurement of roundness. This is misleading.<ref>{{Cite web
|title=A guide to the Measurement of Roundness
|quote=Diameter is not the same as roundness
|publisher=[[Taylor-Hobson]] Precision
|url=http://www.tarkkuustuonti.fi/Kampanjat/Brochure_Roundness_Booklet.pdf
}}</ref>

Although constant diameter is a [[necessary condition]] for roundness, it is not a [[sufficient condition]] for roundness: shapes exist that have constant diameter but are far from round. Mathematical shapes such as the [[Reuleaux triangle]] and, an everyday example, the [[Fifty pence (British coin)|British 50p coin]] demonstrate this.

=== Radial displacements ===
Roundness does not describe radial displacements of a shape from some notional centre point,{{#tag:ref|Even though many practical roundness-measuring machines are based on such a measurement technique, the data processing afterwards removes the influence of the axis position.<ref name="NIST" />|group=note}} merely the overall shape.

This is important in manufacturing, such as for [[crankshaft]]s and similar objects, where not only the roundness of a number of [[bearing journal]]s must be measured, but also their alignment on an axis. A bent crankshaft may have perfectly round bearings, yet if one is displaced sideways, the shaft is useless. Such measurements are often performed by the same techniques as for roundness, but also considering the centre position and its relative position along an additional axial direction.

== Calculation in two-dimensions ==
A single trace covering the full rotation is made and at each equally spaced angle, <math>\theta_i</math>, a measurement, <math>R_i</math>, of the radius or distance between the center of rotation and the surface point. A least-squares fit to the data gives the following estimators of the parameters of the circle:<ref name="NIST" >[http://www.itl.nist.gov/div898/handbook/mpc/section3/mpc344.htm Roundness measurements] at [[NIST]]</ref>
:<math>
\hat{R} = \frac{1}{N}\sum\limits_{i=1}^N R_i
</math>

:<math>
\hat{a} = \frac{2}{N} \sum\limits_{i=1}^N R_i \cos{\theta_i}
</math>

:<math>
\hat{b} = \frac{2}{N} \sum\limits_{i=1}^N R_i \sin{\theta_i}
</math>

The deviation is then measured as:

:<math>
\hat{\Delta} = R_i - \hat{R} - \hat{a} \cos{\theta_i} - \hat{b} \sin{\theta_i}
</math>

==Roundness measurements==
[[File:RON-Pilot.jpg|thumb|Roundness measurement]]
Roundness measurement is very important in [[metrology]]. It includes measurement of a collection of points.

==Methods==
For this two fundamental methods are followed:

===Intrinsic datum method===
#The round object is placed over a flat plate and the point of contact is taken as the datum point. Again a dial gauge is placed over the round object and the object is rotated keeping the datum at constant position. Thus the error in roundness can be directly known by comparing the peak height as measured by the dial gauge.
#Alternatively a V shaped base can be used instead of a flat plate. Here will be two datum points will exist instead of one because of obvious reason that our base is V-shaped. The error in roundness can be measured similar to the previous method.
#Also a cylindrical body can be clamped between two axle centres. Here also the dial gauge is mounted over the cylindrical body and thus the roundness is measured by similar procedure as above.

===Extrinsic datum method===
The intrinsic method is limited to small deformations only. For large deformations extrinsic method has to be followed.In this case the datum is not a point or set of points on the object, but is a separate precision bearing usually on the measuring instrument. The axis of the object or part of the object to be measured is aligned with the axis of the bearing. Then a stylus from the instrument is just made to touch the part to be measured. A touch sensor connected to the tip of the stylus makes sure that the stylus just touches the object. A minimum of three readings are taken and an amplified polar plot is drawn to get the required error.

==Roundness error definitions==
*Least square circle (LSC): It is a circle which separates the roundness profile of an object by separating the sum of total areas of the inside and outside it in equal amounts. The roundness error then can be estimated as the difference between the maximum and minimum distance from this reference circle
*Minimum Zone circle (MZC): Here two circles are used as reference for measuring the roundness error. One circle is drawn outside the roundness profile just as to enclose the whole of it and the other circle is drawn inside the roundness profile so that it just inscribes the profile. The roundness error here is the difference between the radius of the two circles.
*Minimum circumscribed circle (MCC): It is defined as the smallest circle which encloses whole of the roundness profile. Here the error is the largest deviation from this circle
*Maximum inscribed circle (MIC): It is defined as the largest circle that can be inscribed inside the roundness profile. The roundness error here again is the maximum deviation of the profile from this inscribed circle.

== See also ==
*[[Compactness measure of a shape]]
*[[Eccentricity (mathematics)]], how much a conic section (e.g., ellipse) deviates from being circular
*[[Geometric dimensioning and tolerancing]]
*[[Surface roughness]]
*[[Sphericity]]

== Notes ==
{{Reflist|group=note|liststyle=lower-roman}}

== References ==
{{Reflist}}

== External links ==
*[http://www.howround.com/ How round is your circle?] Contains a chapter giving an introduction to roundness testing.
*[http://people.uncw.edu/dockal/gly312/grains/grains.htm Grain Morphology: Roundness, Surface Features, and Sphericity of Grains]{{dead link|date=August 2013}}

[[Category:Metrology]]