text:
User talk:CrazyEddy

External link
"Content required" means that essentially this is an advert and an advert for "consultancy" is not required by Wikibooks (which requires content for a reader rather than links). There is nothing directly applicable to the autistic spectrum on the website (which is what the page is about). I will removed the link. If you do not agree please take it up on the talk page rather than replacing it. Thanks -- Herby talk thyme 13:27, 12 December 2006 (UTC)

Google "links"
Just to let you know these do not work for me at least -- Herby talk thyme 16:37, 16 December 2006 (UTC)
 * Check them out - the bottom one works, the middle one gets me the Wikibooks page only, the top one doesn't get me anything. Sorry but do test them if you are going to put them in -- Herby  talk thyme 17:00, 16 December 2006 (UTC)

More!
Hello and welcome to Wikibooks!

Here are some tips to help you get started:
 * You should sign your name on Talk and vote pages using four tildes, like this: ~~~~.
 * Remember to conduct any editing experiments in the sandbox.
 * If you're a Wikipedian, see Wikibooks for Wikipedians for a primer on how things work here (it's a little different).
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 * Explore, be bold in editing pages, and have fun!

You will find more resources in Community Portal. If you want to ask a question, visit the Study help desk, the Staff lounge, IRC channel or ask me personally on my talk page. For site news, see the Bulletin board. It might be an idea if you add this page to your "watchlist" so that you can see when any new information is posted there.

Good luck!

Should have done that before sorry. So thanks for fixing the links - I learnt something myself cos I didn't know you could link to google that way!. As to abusing the senses I hope not. Look at fixing (for readability) the link using the "|" sign - I've done the "middle one" as an eg. If I can help let me know. Regards -- Herby talk thyme 18:33, 16 December 2006 (UTC)

Post on talk page of 'Survival Guide for People with Autism' regarding copyright
Hi,

I've posted a topic about copyright rights on the talk page of the book 'Survival Guide for People with Autism'. There I explain about my uncertainty of if the book is fully free.(ie. we/you know that the authors have agreed/'given their consent' to the licenses used on wikibooks. That wikibooks is not a website that hosts all kinds of books but specifically books that are considered "free" in a libre sense. Thank you for your time. Logictheo (talk) 08:37, 13 June 2010 (UTC)

title: User talk:CrazyEddy


text:
User talk:Ernie741

Hello and welcome to Wikibooks!

Here are some tips to help you get started:
 * You should sign your name on Talk and vote pages using four tildes, like this: ~~~~.
 * Remember to conduct any editing experiments in the sandbox.
 * If you're a Wikipedian, see Wikibooks for Wikipedians for a primer on how things work here (it's a little different).
 * If you want to base your work here on materials from Wikipedia, please use WB:RFI to bring the material over in compliance with the GFDL.
 * If you're an instructor and plan on using wikibooks for a class project, see Guidelines for class projects
 * Please say hello at the Staff Lounge with any questions or ideas.
 * Eventually, you might want to read the Manual of Style and Policies and Guidelines.
 * Please take a look at Naming policy before starting a new book.
 * Remember to maintain a Neutral point of view.
 * Explore, be bold in editing pages, and have fun!

You will find more resources in Community Portal. If you want to ask a question, visit the Study help desk, the Staff lounge, IRC channel or ask me personally on my talk page. For site news, see the Bulletin board. It might be an idea if you add this page to your "watchlist" so that you can see when any new information is posted there.

Good luck! -- Herby talk thyme 13:41, 12 December 2006 (UTC)

Copyright
I have replied to your query on the talk page of the article - thanks -- Herby talk thyme 13:41, 12 December 2006 (UTC)

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/

title: User talk:Ernie741


text:
Chess Opening Theory/1. e4/1...e6/2. d4/2...d5/3. Nd2/3...c5

=French Defence: Tarrasch Variation=

Theory table
.

'''1. e4 e6 2. d4 d5 3. Nd2 c5''' Black's best chance for equality is to strike at d4 since the White queen's defense has been blocked. Play can be similar to the Alapin Sicilian.


text:
User talk:194.196.10.97

Thanks for experimenting with Wikibooks. Your test worked, and has now been removed. Please use Sandbox for any other tests you want to do, since testing material in modules will normally be removed quickly. Please see the welcome page if you would like to learn more about contributing to our project. Thanks. -- Herby talk thyme 14:44, 12 December 2006 (UTC)

title: User talk:194.196.10.97


text:
Talk:Data Structures/Tradeoffs

An array may be used to create a queue if his cells are used in a cyclic way.

title: Talk:Data Structures/Tradeoffs


text:
User:Mloskot

Mateusz Łoskot

Homepage: http://mateusz.loskot.net

E-mail: mateusz at loskot dot net

title: User:Mloskot


text:
Talk:Converting MySQL to PostgreSQL

There is no DATETIME type in PostgreSQL. I have an impression MySQL and PostgreSQL types are replaced in the table.

Cf. for a difference between DATETIME and TIMESTAMP in MySQL.

There should be some info that you can retrieve data like "SHOW table" (MYSQL) in PostgreSQL too by using SQL statements or programming language interfaces, not just by tools.

Look for pg system tables and/or INFORMATION_SCHEMA.
 * information_schema is in MySQL 5 as well. I don't know if they're exactly the same in both but it might be worth mentioning.

Why not use MD5 instead of password for authentication?

Helper tool?
Isn't it possible to create one program which one could give the mysql dump and it converts it to a pg-insertable dump? Or is there already one I have greatly missed? (If so, please link to it ;) AFAIS that would be a bit of work (and maybe a little headache too), but no rocket-science. Am I wrong, or hasn't the effort simply been made yet?

I suggest mentioning this in the intro section (to clarify why one needs this book at all).

REPLACE and ON DUPLICATE KEY UPDATE replacements
Personally I feel that the provided alternative isn't the most appropriate one. It isn't very clear how to use it as is and there is a risk of a "duplicate key violation" when multiple transactions try to do the same. PostgreSQL themselves already provide a pretty good alternative and with a slight modification it can be made clear how people can apply it:

CREATE FUNCTION insertOrUpdate(key INT, data TEXT, [...]) RETURNS VOID AS $$ BEGIN LOOP -- first try to update the key UPDATE table SET datacolumn = data WHERE keycolumn = key; IF found THEN RETURN; END IF; -- not there, so try to insert the key -- if someone else inserts the same key concurrently, -- we could get a unique-key failure BEGIN INSERT INTO table(keycolumn, datacolumn) VALUES (key, data); RETURN; EXCEPTION WHEN unique_violation THEN -- do nothing, and loop to try the UPDATE again END; END LOOP; END; $$ LANGUAGE plpgsql;

Yet another alternative would be: CREATE RULE insertOrUpdate AS 	ON INSERT TO table WHERE EXISTS(SELECT 1 FROM table WHERE keycolumn = NEW.key) DO INSTEAD (UPDATE table SET datacolumn = NEW.data WHERE keycolumn = NEW.key);

These alternatives are technically only an alternative for ON DUPLICATE KEY UPDATE, just like the current alternative, not REPLACE. I found the changes a bit too drastic to just apply so I'd like to hear your opinions first. Prodoc (talk) 21:11, 8 September 2010 (UTC)

Using_pgloader
Are there meant to be three forward slashes in the code example under Using pgloader?

pgloader mysql://user@localhost/dbname postgresql:///dbname

--212.237.130.90 (discuss) 10:43, 11 November 2018 (UTC)

title: Talk:Converting MySQL to PostgreSQL


text:
Wikibooks:Ownership

At Wikibooks, editors are encouraged to be bold in their editing practices. When disagreements arise, writing and editorial decisions are made collaboratively. This policy explains the limitations that apply in what you can control when doing work at Wikibooks. These limitations may not apply to works forked outside Wikibooks and should not be confused for the licensing terms of use.

Ownership
By contributing, you agree not to assert authority or control over books, and to allow anyone to edit, modify, delete, and fork books at Wikibooks. You may not prevent others from editing or modifying content. This is true regardless of who started the page or who has contributed "the most" to the book. If you wish to prevent others from editing or modifying content, you may fork pages or books outside Wikibooks, where you can assert whatever editorial control over the copy you use within the licensing terms of use.

Behavior that other contributors view as ownership may not mean an explicit claim to owning the book. More frequently, the term is used to describe an unwillingness to discuss or compromise. One clear indicator of a problem is when one contributor repeatedly reverts or otherwise removes the work of other contributors. Because of the hard work involved in creating a book, strong opinions about the book's content are natural, but if you find yourself doing this, then it is time to stop and discuss. A willingness to discussion and compromise keeps everyone on equal terms in deciding what goes into books.

Wikibooks Administrators can protect pages from being edited as a deterrent to vandalism and edit warring. Page protection in this sense should not be used to exercise control over the contents of a page, and any editorial control can only be enforced by community decisions, policies, or guidelines.

Do not contribute your content to Wikibooks if you do not want other people using your contents in whatever way they want without your express permission.

title: Wikibooks:Ownership


text:
User:Whiteknight/Behavior Summary

Wikibooks is a community of people not just a webserver filled with e-books. As such, it is important that people treat each other in kind and constructive ways.

Do Unto Others
Wikibookians are encouraged to be civil towards one another, if they absolutely cannot be completely nice. Give others the benefit of the doubt when they do something you disagree with. Don't insult people, use bad language, or otherwise be unpleasant. Also, when possible, help out the new users. If every new user gets off to the right foot, wikibooks will be a better place.

See Also:
 * 1) Be civil
 * 2) Profanity
 * 3) No personal attacks
 * 4) Please do not bite the newcomers

Accept What You Should Not Change
Wikibooks is a collaborative project, and as such, there are many different people contributing to it. Anything that you contribute could be fixed, edited, revised, altered, or even deleted completely (although the latter shouldn't happen unless you've made a big mistake). This is normal, and is even encouraged. Unfortunately, this also means that you can't control projects you work on, and that you can't prevent other people from contributing to them. If you see people doing things differently from you, talk to them, work together, and find a good middle ground.

See Also:
 * 1) Ownership

title: User:Whiteknight/Behavior Summary


text:
User:Whiteknight/Content Summary

Anybody may be able to edit wikibooks, but that doesn't mean that all edits and all contributions are allowed to stay here. Wikibooks has some important rules to follow concerning what types of content can be added to our project. If you add content that isn't allowed, the content could be deleted, and (in extreme cases) you could be blocked from wikibooks all together.

What Can't be Contributed
Wikibooks is a place for writing collaborative textbooks. Textbooks typically are used to convey information that is already known by the experts to the new students in the subject. For that reason, Wikibooks is not the correct place to write about new information. Anything that is new, original, or novel does not belong on wikibooks.

Textbooks also are informational works, not propaganda. For that reason, all material on wikibooks must maintain strict neutrality. You can not write to convince other people about your political ideologies, your religious beliefs, or any other biased information.

Even though you can add content to wikibooks at will, you should only use wikibooks for the creation of textbooks. Wikibooks shouldn't be used as a discussion forum, a blog, a bulletin board for outside projects, or a personal webhost for information that doesnt relate to our goals of writing textbooks. That information might all have some value, but it doesnt belong here.

See Also:
 * 1) What is Wikibooks?
 * 2) Original research
 * 3) Neutral point of view

What Can be Contributed
Textbooks require text, certainly, but also images and diagrams and tables. All text contributed to Wikibooks must be licensed under the GFDL, but images and other media can be licensed under a number of other free licenses, such as the Creative Commons licenses, the BSD license, or even can be released into the public domain.

Images can be uploaded to the wikibooks server, or they can be uploaded to Wikimedia Commons. Commons is a webserver that stores images for use on many projects, wikibooks, wikipedia, and wikiversity all share images with Commons. If you have an image you would like to upload, consider uploading it at wikimedia commons, so everybody can share it.

See Also:
 * 1) Copyrights
 * 2) GNU Free Documentation License
 * 3) Image use policy

title: User:Whiteknight/Content Summary


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User:Whiteknight/Contributions Summary

Wikibooks is a collaborative community, where people work together to write open-content textbooks. However, because there is no firm organizational or editorial structure at wikibooks, there are bound to be questions about who gets to edit what when, and who gets the final say, and who gets to make changes.

Who Gets the Final Say?
No one person has the authority to make decisions, and nobody gets the "final say" on any matter. Wikibooks, and the individual book subprojects on wikibooks are not monarchies, and there is no "king of wikibooks". All decisions should be made by concensus from the community at large. Notice that "concensus" is not the same thing as "majority rule". Wikibooks is also not a democracy, and majority voting is not an appropriate way to solve disputes. If you have a disagreement with other editors, work it out, discuss it, and compromise. Compromise is the most important skill you can have here on wikibooks.

See Also:
 * 1) Decision making

How Are Changes Made?
Concensus is a slow process for making new changes, especially when those changes are small, or if there isn't really going to be any opposition anyway. The general motto here at wikibooks is "Be Bold!". If you see a change that needs to be made, make it. If you see something that needs to be improved, improve it! If, however, your changes are met with opposition, you must then rely on concensus, discussion, and compromise to find the best solutions to the problem.

See Also:
 * 1) Be bold
 * 2) Editing guideline

Who Is In Charge?
You are! It is up to you to make changes where you feel they are necessary. It is up to you to contribute content that you are able. Nobody is going to tell you what to do, or when to do it. Wikibooks does have certain community members who are active on a wide scale, and who have been informally dubbed "staff". Wikibooks staff are available to you to ask questions, and to provide help. To get in touch with a staff member, ask a question on the Staff lounge. If you would like to become a staff member, there is no process involved, just help out and answer other people's questions too!

How are Books Made?
You make them! If you want to contribute content, please feel free to do so. However, if you would like to start an entirely new book, that's fine too. Books take alot of work, and a lot of planning so make sure that you don't rush into it and get in over your head. In a worst-case scenario, your new book could become so bad and unusable, that it could get deleted! A new book should be properly named, should be properly organized, and should follow all the applicable conventions and style guidelines. Once you create a new book, leave a note about it on the New Books Staff Lounge, a page where new users can announce their new projects (or just say hello).

See Also:
 * 1) Manual of Style
 * 2) Bookshelves
 * 3) Naming policy

title: User:Whiteknight/Contributions Summary


text:
User:Whiteknight/Administration Summary

Wikibooks is a large place, and in addition to the contribution of textbook content, there is alot of work done by volunteers to keep this place clean, organized, and running smoothly.

Wikibooks Staff
There are some contributors who, in addition to contributing textbook content, also work to make wikibooks a better place. These people are informally dubbed "staff". Wikibooks staff might help answer questions, or they may come to help fix your formatting and grammar, or they may even participate in discussions that affect the project as a whole. Some staff members help to fight vandalism, some work to organize books, some write policy and guidelines, some write in the help book, and some do a little of everything!

How do I Become Staff?
You get to decide your own level of involvment in the wikibooks project. If you want to be a staff member, all you need to do is start acting like a staff member. See a new user who needs help? Help! See vandalism? Clean it! See a discussion? Join in and express your opinions. There are all sorts of things that you can do right now to help out the wikibooks project.

What are "Administrators"?
Administrators are staff members who have some additional tools. These additional tools, such as the power to delete pages, and the power to block malicious vandals, are necessary for the operation of wikibooks, but require a certain amount of trust in order to get them. Administrators are nominated and voted on at Requests for adminship. Remember, Administrators have large responsibilities, and voting for a new administrator should never be a popularity contest.

Administrators, while well-trusted, do not have any additional authority here on Wikibooks. The oldest, most trusted administrator has just as much say in a discussion as the newest of new users.

See Also:
 * 1) Administrators
 * 2) Requests for adminship

How Do We Get Rid of Garbage?
Some pages just don't belong here on wikibooks, and following a discussion, they can be deleted. Pages that might need to be deleted are nominated on Votes for deletion. Following that discussion, if the community agrees, an administrator will delete the page. Participating in these discussions, known as "VfD Discussions" is a great and easy way to get involved in the wikibooks community, and to learn more about wikibooks policy.

See Also:
 * 1) Deletion policy
 * 2) Votes for deletion

How Do We Fight Vandalism?
Only an administrator can block vandals from editing but any user, even you, can help to fix the damage caused by these vandals. If you see vandalism, fix it, and post an alert on Vandalism in progress. When an admin sees your note, he will block the vandal, and help with the cleanup effort.

See Also:
 * 1) Vandalism in Progress

title: User:Whiteknight/Administration Summary


text:
Common Lisp/Advanced topics/Strings

The most important thing to know about strings in Common Lisp is probably that they are arrays and thus also sequences. This implies that all concepts that are applicable to arrays and sequences also apply to strings. If you can't find a particular string function, make sure you've also searched for the more general array or sequence functions. We'll only cover a fraction of what can be done with and to strings here.

Accessing Substrings
As a string is a sequence, you can access substrings with the SUBSEQ function. The index into the string is, as always, zero-based. The third, optional, argument is the index of the first character which is not a part of the substring, it is not the length of the substring.

You can also manipulate the substring if you use SUBSEQ together with SETF.

But note that the string isn't "stretchable". To cite from the HyperSpec: "If the subsequence and the new sequence are not of equal length, the shorter length determines the number of elements that are replaced." For example:

Accessing Individual Characters
You can use the function CHAR to access individual characters of a string. CHAR can also be used in conjunction with SETF.

Note that there's also SCHAR. If efficiency is important, SCHAR can be a bit faster where appropriate.

Because strings are arrays and thus sequences, you can also use the more generic functions AREF and ELT (which are more general while CHAR might be implemented more efficiently).

Manipulating Parts of a String
There's a slew of (sequence) functions that can be used to manipulate a string and we'll only provide some examples here. See the sequences dictionary in the HyperSpec for more.

Another function that can be frequently used (but not part of the ANSI standard) is replace-all. This function provides an easy functionality for search/replace operations on a string, by returning a new string in which all the occurrences of the 'part' in string is replaced with 'replacement'".

One of the implementations of replace-all is as follows:

However, bear in mind that the above code is not optimized for long strings; if you intend to perform such an operation on very long strings, files, etc. please consider using cl-ppcre regular expressions and string processing library which is heavily optimized.

Concatenating Strings
The name says it all: CONCATENATE is your friend. Note that this a generic sequence function and you have to provide the result type as the first argument.

If you have to construct a string out of many parts, all of these calls to CONCATENATE seem wasteful, though. There are at least three other good ways to construct a string piecemeal, depending on what exactly your data is. If you build your string one character at a time, make it an adjustable VECTOR (a one-dimensional ARRAY) of type character with a fill-pointer of zero, then use VECTOR-PUSH-EXTEND on it. That way, you can also give hints to the system if you can estimate how long the string will be. (See the optional third argument to VECTOR-PUSH-EXTEND.)

If the string will be constructed out of (the printed representations of) arbitrary objects, (symbols, numbers, characters, strings, ...), you can use FORMAT with an output stream argument of NIL. This directs FORMAT to return the indicated output as a string.

We can use the looping constructs of the FORMAT mini language to emulate CONCATENATE.

FORMAT can do a lot more processing but it has a relatively arcane syntax. After this last example, you can find the details in the CLHS section about formatted output.

Another way to create a string out of the printed representation of various object is using WITH-OUTPUT-TO-STRING. The value of this handy macro is a string containing everything that was output to the string stream within the body to the macro. This means you also have the full power of FORMAT at your disposal, should you need it.

Joining Strings With a Delimiter
Even though the previous section provides enough hints on how to do that, it may be the right time and place to stress how to join strings using delimiters. Assume you have a list of numbers or strings such as (192 168 1 1) or ("192" "168" "1" "1") and you want to join them with the delimiter "." or ";" to create another string. Here are some examples:

Processing a String One Character at a Time
Use the MAP function to process a string one character at a time.

Or do it with LOOP.

Reversing a String by Word or Character
Reversing a string by character is easy using the built-in REVERSE function (or its destructive counterpart NREVERSE).

There's no one-liner in CL to reverse a string by word (like you would do it in Perl with split and join). You either have to use function from an external library like SPLIT-SEQUENCE or you have to roll your own solution. Here's an attempt:

Controlling Case
Common Lisp has a couple of functions to control the case of a string.

These functions take :START and :END keyword arguments so you can optionally only manipulate a part of the string. They also have destructive counterparts whose names starts with "N".

Note this potential caveat: According to the HyperSpec, "for STRING-UPCASE, STRING-DOWNCASE, and STRING-CAPITALIZE, string is not modified. However, if no characters in string require conversion, the result may be either string or a copy of it, at the implementation's discretion." This implies the last result in the following example is implementation-dependent - it may either be "BIG" or "BUG". If you want to be sure, use COPY-SEQ.

Trimming Blanks from the Ends of a String
Not only can you trim blanks, but you can get rid of arbitrary characters. The functions STRING-TRIM, STRING-LEFT-TRIM and STRING-RIGHT-TRIM return a substring of their second argument where all characters that are in the first argument are removed off the beginning and/or the end. The first argument can be any sequence of characters.

Note: The caveat mentioned in the section about Controlling Case also applies here.

Converting between Symbols and Strings
The function INTERN will "convert" a string to a symbol. Actually, it will check whether the symbol denoted by the string (its first argument) is already accessible in the package (its second, optional, argument which defaults to the current package) and enter it, if necessary, into this package. It is beyond the scope of this chapter to explain all the concepts involved and to address the second return value of this function. See the CLHS chapter about packages for details.

Note that the case of the string is relevant.

To do the opposite, convert from a symbol to a string, use SYMBOL-NAME or STRING.

Converting between Characters and Strings
You can use COERCE to convert a string of length 1 to a character. You can also use COERCE to convert any sequence of characters into a string. You can not use COERCE to convert a character to a string, though - you'll have to use STRING instead.

Finding an Element of a String
Use FIND, POSITION, and their -IF counterparts to find characters in a string.

Or use COUNT and friends to count characters in a string.

Finding a Substring of a String
The function SEARCH can find substrings of a string.

Converting a String to a Number
CL provides the PARSE-INTEGER to convert a string representation of an integer to the corresponding numeric value. The second return value is the index into the string where the parsing stopped.

PARSE-INTEGER doesn't understand radix specifiers like #X, nor is there a built-in function to parse other numeric types. You could use READ-FROM-STRING in this case, but be aware that the full reader is in effect if you're using this function.

Converting Number to a String
Common Lisp provides functions such as PRINC-TO-STRING and PRIN1-TO-STRING to convert numbers into strings. If you want to concatenate a string and a number you can use them as follows:

Comparing Strings
The general functions EQUAL and EQUALP can be used to test whether two strings are equal. The strings are compared element-by-element, either in a case-sensitive manner (EQUAL) or not (EQUALP). There's also a bunch of string-specific comparison functions. You'll want to use these if you're deploying implementation-defined attributes of characters. Check your vendor's documentation in this case.

Here are a few examples. Note that all functions that test for inequality return the position of the first mismatch as a generalized boolean. You can also use the generic sequence function MISMATCH if you need more versatility.

Splitting Strings
SPLIT-SEQUENCE is part of the Common Lisp Utilities collection, available at http://www.cliki.net/SPLIT-SEQUENCE.

Copyright © 2002-2005 The Common Lisp Cookbook Project

title: Common Lisp/Advanced topics/Strings


text:
Horticulture/Chicory

Chicory is the common name given to the flowering plants in genus Cichorium of the family ../Asteraceae/. There are two cultivated species, and four to six wild species.

Common chicory (Cichorium intybus) is a bushy perennial herb with blue or lavender flowers. Originating from Europe, it was naturalized in North America, where it has become a roadside weed. The roots are baked, ground, and used as a coffee substitute and additive in the plant's Mediterranean region of origin, although its use as a coffee additive is still very popular in the American South, particularly in New Orleans, Louisiana. Common chicory is also known as blue sailors, succory, and coffeeweed. The plant is cultivated and used as endive under the common names radicchio, Belgian endive, French endive, or witloof. It is grown in complete darkness to keep new leaves tender and pale.

Root chicory (Chicorium intybus var. sativum) has been grown since the Middle Ages as a coffee substitute. Around 1970 it was found that the root contains up to 20% inulin. Since then, new strains have been created, giving root chicory an inulin content comparable to that of sugar beet (around 600 dt/ha). Inulin is mainly present in the plant family Asteraceae as a storage carbohydrate (for example Jerusalem artichoke, dahlia, etc.). It is used as a sweetener in the food industry (with a sweetening power 30% higher than that of sucrose). Inulin can be converted to fructose and glucose through hydrolysis.

Chicory, with sugar beet and rye was used as an ingredient of the East German Mischkaffee (mixed coffee), introduced during the 'coffee crisis' of 1976-1979. Chicory, especially the flower, was used as a treatment in Germany, and is recorded in many books as an ancient German treatment for everyday ailments.

True endive (Cichorium endivia) is a species of chicory which is specially grown and used as a salad green. It has a slightly bitter taste and has been attributed with herbal properties. Curly endive and the broad-leafed escarole are true endives. C. Endiva root is used ethnomedically to treat dyspepsia, loss of appetite, liver and gallbladder problems, and intestinal worms, Type II Diabetes, and as a laxative for children.

Pests and diseases
Several pests and disease problems can occur both on cultivated plants and on weeds, which can serve as secondary hosts for problems affecting nearby garden plants.

Arthropod pests

 * Bean aphid
 * Pea aphid
 * Lettuce aphid (Nasonovia ribis-nigri)
 * Peach aphid (Myzus persicae)
 * Setaceous Hebrew Character
 * ../Agrotis segetum/ (Turnip Moth) is a severe pest of chicory root.
 * Leaf miners (Liriomyza spp)

Pathogens

 * Mosaic: Turnip mosaic virus
 * Blight: Botrytis cinerea
 * Root and crown rots: Rhizoctonia solani, Pythium spp., Fusarium spp., Sclerotinia sclerotiorum, Sclerotinia minor, and ../Phytophthora/ spp.
 * Damping-off: Rhizoctonia solani and Pythium spp.
 * Bacterial rots: Xanthomonas spp., Pseudomonas spp., and Erwinia chrysanthemi
 * Anthracnose: Microdochium panattonianum
 * Downy mildews: Bremia lactucae

title: Horticulture/Chicory


text:
Transwiki:Fibonacci number

In mathematics, the Fibonacci numbers form a sequence defined recursively by:

F(n)= \left\{ \begin{matrix} 0\,,\qquad\qquad\qquad\quad\,\ \ \,&&\mbox{if }n=0\,;\ \ \\ 1,\qquad\qquad\qquad\qquad\,&&\mbox{if }n=1;\ \ \,\\ F(n-1)+F(n-2)&&\mbox{otherwise.} \end{matrix} \right. $$ In words: you start with 0 and 1, and then produce the next Fibonacci number by adding the two previous Fibonacci numbers. The first Fibonacci numbers (sequence A000045 in OEIS) for n = 0, 1,... are
 * 0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233, 377, 610, 987, 1597, 2584, 4181, 6765, 10946...

A tiling with Fibonacci number sized squares

Origins
This sequence was first described by Leonardo of Pisa, who was also known as Fibonacci (c. 1200), to describe the growth of a rabbit population. The numbers describe the number of pairs in a (somewhat idealized) rabbit population after n months if it is assumed that
 * the first month there is just one newly born pair,
 * newly born pairs become productive from their second month on,
 * we have no genetic problems whatsoever generated by inbreeding,
 * each month every productive pair begets a new pair, and
 * the rabbits never die

The formula above applies to the rabbit problem because if in month n we have a rabbits and in month n + 1 we have b rabbits then in month n + 2 we'll necessarily have a + b rabbits. That's because we know each rabbit basically gives birth to another each month (actually each pair gives birth to another pair, but it is the same thing) and that means that all a rabbits give birth to another number of a rabbits which will become fertile after two months, which is exactly at month n + 2. That's why we have the population at moment n + 1 (which is b) plus exactly the population at moment n (which is a).

The term Fibonacci sequence is also applied more generally to any function g where g(n + 2) = g(n) + g(n + 1). These functions are precisely those of the form g(n) = aF(n) + bF(n + 1) for some numbers a and b, so the Fibonacci sequences form a vector space with the functions F(n) and F(n + 1) as a basis.

In particular, the Fibonacci sequence L with L(1) = 1 and L(2) = 3 is referred to as the Lucas numbers. This sequence was described by Leonhard Euler in 1748, in the Introductio in Analysin Infinitorum. The significance in the Lucas numbers L(n) lies in the fact that raising the Golden ratio to the nth power yields:

 * $$\left( \frac 1 2 \left( 1 + \sqrt{5} \right) \right)^n = \frac 1 2 \left( L(n) + F(n) \sqrt{5} \right) $$

Lucas numbers are related to Fibonacci numbers by the relation:

 * $$L(n) = F(n-1) + F(n+1)$$

Explicit formula
As was pointed out by Johannes Kepler, the ratio of adjacent Fibonacci numbers, i.e. $$F(n+1)/F(n)$$, converges to the golden mean φ. In modern form:
 * $$x=\lim_{n\to\infty}\frac{F(n+1)}{F(n)}$$$$

=\lim_{n\to\infty}\frac{F(n)+F(n-1)}{F(n)}$$$$ =1+\lim_{n\to\infty}\frac{F(n-1)}{F(n)}$$$$ =1+\frac1{\lim_{n\to\infty}\frac{F(n)}{F(n-1)}}$$$$ =1+\frac1x$$ or $$x^2=x+1$$, a quadratic equation with $$\phi, 1-\phi$$ as solutions. If we multiply both sides by $$x^n$$, we get $$x^{n+2}=x^{n+1}+x^n$$. Thus the two functions $$n\mapsto\phi^n$$ and $$n\mapsto(1-\phi)^n$$ — as well as all linear combinations $$n\mapsto a\phi^n+b(1-\phi)^n$$ — satisfy the Fibonacci recurrence.

By adjusting the coefficients to get the proper initial values F(0) = 0 and F(1) = 1, we obtain

 * $$F\left(n\right) = {\phi^n \over \sqrt{5}} - {(1-\phi)^n \over \sqrt{5}}$$

This genrerates the closed form formula for the Fibonacci numbers as

 * $$F\left(n\right) = { (1+\sqrt{5})^n-(1-\sqrt{5})^n \over \sqrt{5}\cdot2^n }$$

This result can also be derived using the technique of generating functions, or the technique of solving linear recurrence relations.

As n goes to infinity, the second term converges to zero, so the Fibonacci numbers approach the exponential φn/√5, hence their convergent ratios. In fact the second term starts out small enough that the Fibonacci numbers can be obtained from the first term alone, by rounding to the nearest integer.

Computing Fibonacci numbers
Computing Fibonacci numbers by computing powers of the golden mean is not very practical except for small values of n, since rounding errors will accrue and floating point numbers usually don't have enough precision.

The straightforward recursive implementation of the Fibonacci sequence definition is also not advisable, since it would compute many values repeatedly (unless the programming language has a feature which allows the storing of previously computed function values). Therefore, one usually computes the Fibonacci numbers "from the bottom up", starting with the two values 0 and 1, and then repeatedly replacing the first number by the second, and the second number by the sum of the two.

For huge arguments and if a bignum system is being used, a faster way to calculate Fibonacci numbers uses the following matrix equation:

 * $$\begin{bmatrix} 1 & 1 \\ 1 & 0 \end{bmatrix}^n =

\begin{bmatrix} F\left(n+1\right) & F \left(n\right) \\ F\left(n\right)  & F \left(n-1\right) \end{bmatrix} $$

and employs exponentiating by squaring.

Applications
The Fibonacci numbers are important in the run-time analysis of Euclid's algorithm to determine the greatest common divisor of two integers.

Matiyasevich was able to show that the Fibonacci numbers can be defined by a Diophantine equation, which led to his original solution of Hilbert's tenth problem.

The Fibonacci numbers occur in a formula about the diagonals of Pascal's triangle (see binomial coefficient).

In music Fibonacci numbers are sometimes used to determine tunings, and, as in visual art, to determine the length or size of content or formal elements. Examples include Béla Bartók's Music for Strings, Percussion, and Celesta.

Generalizations
A generalization of the Fibonacci sequence are the Lucas sequences. One kind can be defined thus:

 * U(0) = 0
 * U(1) = 1
 * U(n+2) = PU(n+1) − QU(n)

where the normal Fibonacci sequence is the special case of P = 1 and Q = -1. Another kind of Lucas Sequence begins with V(0) = 2, V(1) = P. Such sequences have applications in number theory and primality proving.

The Fibonacci polynomials are another generalization of Fibonacci numbers.

Identities

 * F(n + 1) = F(n) + F(n − 1)

 * F(0) + F(1) + F(2) + ... + F(n) = F(n + 2) − 1

 * F(1) + 2 F(2) + 3 F(3) + ... + n F(n) = n F(n + 2) − F(n + 3) + 2

These identities can be proven using many different methods. But, among all, we wish to present an elegant proof for each of them using combinatorial arguments here. In particular, F(n) can be interpreted as the number of ways summing 1's and 2's to n − 1, with the convention that F(0) = 0, meaning no sum will add up to -1, and that F(1) = 1, meaning the empty sum will "add up" to 0. Here the order of the summands matters. For example, 1 + 2 and 2 + 1 are considered two different sums and are counted twice.

Proof of the first identity. Without loss of generality, we may assume n ≥ 1. Then F(n + 1) counts the number of ways summing 1's and 2's to n.

When the first summand is 1, there are F(n) ways to complete the counting for n − 1; and the first summand is 2, there are F(n − 1) ways to complete the counting for n − 2. Thus, in total, there are F(n) + F(n − 1) ways to complete the counting for n. $$\Box$$

Proof of the second identity. We count the number of ways summing 1's and 2's to n + 1 such that at least one of the summands is 2.

As before, there are F(n + 2) ways summing 1's and 2's to n + 1 when n ≥ 0. Since there is only one sum of n + 1 that does not use any 2, namely 1 + … + 1 (n + 1 terms), we subtract 1 from F(n + 2).

Equivalently, we can consider the first occurrence of 2 as a summand. If, in a sum, the first summand is 2, then there are F(n) ways to the complete the counting for n − 1. If the second summand is 2 but the first is 1, then there are F(n − 1) ways to complete the counting for n − 2. Proceed in this fashion. Eventually we consider the (n + 1)-th summand. If it is 2 but all of the previous n summands are 1's, then there are F(0) ways to complete the counting for 0. If a sum contains 2 as a summand, the first occurrence of such summand must take place in between the first and (n + 1)-th position. Thus F(n) + F(n − 1) + … + F(0) gives the desired counting. $$\Box$$

Proof of the third identity. This identity can be establshed in two stages. First, we count the number of ways summing 1's and 2's to -1, 0, …, or n + 1 such that at least one of the summands is 2.

By our second identity, there are F(n + 2) − 1 ways summing to n + 1; F(n + 1) − 1 ways summing to n; …; and, eventually, F(2) − 1 way summing to 1. As F(1) − 1 = F(0) = 0, we can add up all n + 1 sums and apply the second identity again to obtain
 * [F(n + 2) − 1] + [F(n + 1) − 1] + … + [F(2) − 1]
 * = [F(n + 2) − 1] + [F(n + 1) − 1] + … + [F(2) − 1] + [F(1) − 1] + F(0)
 * = F(n + 2) + [F(n + 1) + … + F(1) + F(0)] − (n + 2)
 * = F(n + 2) + F(n + 3) − (n + 2).

On the other hand, we observe from the second identity that there are …… Adding up all n + 1 sums, we see that there are
 * F(0) + F(1) + … + F(n − 1) + F(n) ways summing to n + 1;
 * F(0) + F(1) + … + F(n − 1) ways summing to n;
 * F(0) way summing to -1.
 * (n + 1) F(0) + n F(1) + … + F(n) ways summing to -1, 0, …, or n + 1.

Since the two methods of counting refer to the same number, we have
 * (n + 1) F(0) + n F(1) + … + F(n) = F(n + 2) + F(n + 3) − (n + 2)

Finally, we complete the proof by subtracting the above identity from n + 1 times the second identity. $$\Box$$

Tribonacci number
A tribonacci number is like a Fibonacci number, but instead of starting with two predetermined terms, the sequence starts with three predetermined terms and each term afterwards is the sum of the preceding three terms. The first few tribonacci numbers are:

1, 1, 2, 4, 7, 13, 24, 44, 81, 149, 274, 504, 927, 1705, 3136, 5768, 10609, 19513, 35890, 66012

OEIS number: A000073

Tetranacci number
A tetranacci number is like a tribonacci number, only that starting with four predetermined terms and each term afterwards being the sum of the preceding four terms. The first few tetranacci numbers are

1, 1, 2, 4, 8, 15, 29, 56, 108, 208, 401, 773, 1490, 2872, 5536, 10671, 20569, 39648, 76424, 147312, 283953, 547337

OEIS number: A000078

Pentanacci, hexanacci and heptanacci numbers have been computed, but they have not interested researchers much.

Repfigits
A repfigit or Keith number is an integer, that when its digits start a Fibonacci sequence with that number of digits, the original number is eventually reached. An example is 47, because the Fibonacci sequence starting with 4 and 7 (4,7,11,18,29,47) reaches 47. A repfigit can be a tribonacci sequence if there are 3 digits in the number, a tetranacci number if the number has four digits, etc. The first few repfigits are

14, 19, 28, 47, 61, 75, 197, 742, 1104, 1537, 2208, 2580, 3684, 4788, 7385, 7647, 7909

OEIS number: A007629

title: Transwiki:Fibonacci number


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The Computer Revolution/Hardware/Ram Chips

There are two types of storage, primary and secondary storage. Primary storage deals with temporary storage and is usually called "memory" or "main memory". Secondary storage deals with permanent storage and is usually called "storage". Most memory is referred to storing media, documents...etc on chips, whereas storage stores it on disks or tapes. Memory (primary storage) is stored on RAM chips or Random Access Memory chips. Whenever you open a file from the secondary storage it is opened on the RAM and allows you to make amendments to it. When you save the file it is then moved back to the secondary storage and saved on the hard drive. Basically you can think of the secondary storage as the refrigerator and the primary storage or RAM as the counter or stove in which you cook. There are different types of RAM some which include DRAM, SDRAM, SRAM and DDR - SDRAM. DRAM is abbreviated for "dynamic ram" and is constantly refreshed by the PC to keep its contents. SDRAM is abbreviated for "synchronous dynamic ram" and is synchronized by the system clock. This allows it to be faster than DRAM and the speed is measured in megahertz. SRAM is abbreviated for "static ram" is faster than DRAM and keeps its contents without having to be refreshed by the PC. DDR - SDRAM is abbreviated for "double-data rate synchronous dynamic ram". It is the most current RAM, it is used commonly in PC and Apple's and is also measured in megahertz.


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The Computer Revolution/Computer Graphics/Adobe Photoshop

Photoshop
Whenever there is a mention of photo-editing or photo-retouching or photographs in general, the software that has dominated the market is Adobe Photoshop. Every photographer that I have met who uses digital photography or does photo-editing uses photoshop for skin tones, highlighting, smoothing, etc. But using pictures in artistic ways and creating expressionist or abstract art is an intriguing field of computer graphic designing. Art is relative, what may be art to me may not be considered art by you. With a whole collection of art quotes I will use predominately one quote to justify the contents of this article. "You cannot master art without the knowledge of its technique."

Adobe Photoshop has proved to be a vital tool for me. Rather than just be for editing pictures for fun with friends or for an assignments, it proves to be very easy and efficient when it comes to graphics editing. I am currently using Adobe Photoshop 7 and the wide variety of tools enhances the whole experience. There are tools such as the clone stamp, the burn or dodge tool, paint brush, and many others. There is the optic zoom tool which allows to you to view pictures at 1600%. This basically allows you to perfect every pixel to what you want it to look like. The Clone stamp allows you to copy how every much of another graphic you want in just one easy click and brush stroke. The burn or dodge tool is used to darken a image depending on the intensity you choose. If you hold the Alt key while doing so it does the exact opposite. So if your placing one of your friends head on Arnold Schwarzenegger's body, this makes it easier for you to match the different skin tones. It also allows for you to add text so you can title each picture with some cool fonts and funky colors.

The newest version of Photoshop is Photoshop CS5. It does all the things that previous versions have done but obviously has new features. It is widely used by professional photographers as well as a tool for correcting, manipulating and enhancing photos. One of the greatest things about Photoshop is that you can create actions, which allow the user to record the different tasks performed for that photograph. For example, if you regularly do 10 steps to the majority of your photographs to enhance them, Photoshop allows you to press the record button and continue with those 10 steps and then save that action. Now that it is saved all you have to do is press play in the actions box for the next photograph you want to same 10 steps to take place in. This is one of many features that photographers use in this amazing and multifaceted software.

 * Uses of Photoshop

The uses of Photoshop are plentiful, they vary from modifying photos by simple touch ups such as red eye and clarifying an image. Along with major adjustments such as color saturation, filters and image simulation or design. This allow anyone from a professional artist to a free lance photographer to import and edit any photos. It also allows image manipulation to create the picture you wanted but were unable to get due to weather or the tip of your finger in the photograph.

 * Editing

There are many ways to edit a photograph through the use of Photoshop. It can be a fine detail such increasing the contrast of the photo to allow it to be viewed better. Or complete manipulation of the entire photo. This could take shape and form in discarding the background of a photo and creating your own by substituting another image. However Photoshop is simply not only for photos. The software allows the user to design and manipulate multi-layered pages as well.

 * Manipulation

When approaching manipulation of a photograph it can a daunting experience. Considering that you maybe working on a photograph that has sentimental meaning or possible took you a long time to capture that right shot. Photoshop offers a vast number of ways to properly manipulate your photograph, from blurring the surroundings to concentrate the eye on the center of the image. Or even increasing the proportions of a photo to give it a surreal atmosphere.

 * Tools

Photoshop has about every tool you could possibly need for editing and manipulating you a photo. The tools range from animations, spot healing, red eye tool, smart sharpen and many others. For instance the spot healing tool allows the editor to completely substitute an image out and replace it with background. An example could be a persons hand partially included in a family photo, you could simple use the spot healing tool and completely edit the hand out resulting in the desired photo.


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The Computer Revolution/Software/Application Software

Application Software
Application Software is basically a program that allows you to open, save, amend or program a file on your computer. A common type of application software that in offices is the software suite where are a number of programs all sold together and they are used for different purposes.

Desktop  vs. Mobile Software

Notebook computers, tablet computer, UMPCs and other portable computers run the same application software as desktop computers. Mobile phones and other mobile devices typically require mobile software that is specifically designed for a specific type of mobile phone or other mobile device. A wide range of mobile software is available today. There are mobile compatible versions to popular programs like Word or Powerpoint, games, media players and business tools that record inventory data or keep track of your business expenses, calendars and programs that allow you to organize notes and voice recording, applications that allow you to broadcast your current location to friends and web browsers for accessing web sites. Many mobile applications include features for easier data input, such as an on-screen keyboard, a phrase list, or hand writing recognition capabilities. Some mobile software is designed to be compatible with popular desktop software, such as Microsoft office.

With Mobile phone – we can do lot of things including accessing and searching the Web on most of today’s phones. Web searching is text based; mobile voice search is now available. Mobile voice search allows you to speak, rather than type, search term into your mobile phone and then see the results of that search. With Mobile software application we can able to install Google search, Yahoo search programs into Mobile software and it is easier to use once it is installed in our mobile phones. With Mobile software application it is easier to use while on the go. Commonly requested information includes directions to local businesses, stock quotes, flight information, local restaurants, weather information etc. Both these applications are very useful and essential in today’s busy world.

Software Suites
Software programs that have similar characteristics are often purchased bundled together in a software suite. Software suites used for creating documents are referred to as office suites or productivity software suites. Examples include word processing software, spreadsheet software, database software and presentation graphics software.

Software suites offer advantages to users by providing programs that have a similar interface as well as its often cheaper to purchase the bundle versus each program individually.

It is well known that popular office suites like Microsoft Office is used by many individuals and businesses, there are also free and open-source alternatives to it like LibreOffice or even Google Docs for web users.

Desktop Publishing
Desktop and personal publishing software are used to create attractive documents. The software can manipulate text and images to look as if they came from a professional printer. Although word processing programs can also create attractive documents, desktop publishing is solely designed for this purpose, and can be more efficient. Many people choose to use desktop and personal publishing software for this reason. Some of the documents that can be created are greeting cards, invitations, flyers, calendars, brochures, certificates, and announcements.


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The Computer Revolution/Networks/Short Range Wireless for Personal Area Networks

Short range wireless technology is used to connect personal area networks to personal electronics. These could be your cellphone, you printers, your PDAs, your MP3 players and what not. So far the most famous is Bluetooth which is now joined with Ultra wideband (UWB). It is also connected with wireless USB. Bluetooth connects cellphones, PDAs, computers and other external devices on PCs. It is a short range wireless device so it can connect to devices up to 30 feet away. Bluetooth was at first designed to replace the hassle of cables that were connecting PCs to external devices such as printers and scanners and to overcome "line of sight" problems by using infrared transmission. The original version of Bluetooth technology could transmit up to 720 kilobits per second and was name after Harold Bluetooth who was a Danish King who united Norway and Denmark. The Ultra wideband was a technology developed by the military to increase transfer speeds to up to 480 megabits per second. At a 30 feet connection UWB sent out millions of waves of radio energy at different frequencies every second. The broken bits were then reassembled by the UWB receiver. Sometime along in this year it is predicted that cellphones will inherit this technology and will be able to transfer media from their PCs to their cellphones without adapters or cables. Wireless USB is based on this same technology (UWB). Ranging up to 32 feet it can still transfer up to 480 megabits per second and is said to be a natural replacement for USB cables.


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Revit User's Manual/Modelling

While Revit may appear to be a modeling program in reality it is a database with graphical, text and calculated queries. You may add or delete views without changing the model. The advantage of structuring the program like a database is that things that appear in more than one view when changed are changed in all views. The program has a built in error checking to alert user when something is moved to an invalid location - like two walls overlapping or a door outside of a wall.

title: Revit User's Manual/Modelling


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Cookbook:Homemade Pie Crust

| Dessert | Vegan Cuisine

Unlike with bread, pie crust and other pastries should be made in a way that minimizes the development of gluten. Once the water has been added, the dough should be worked as little as possible, to minimize toughness in the finished crust.

Ingredients

 * 225 grams (1 cup) all-purpose flour
 * 2.5 ml (½ teaspoon) salt
 * 230 ml (1 cup) cold vegetable shortening
 * 30 ml (2 tablespoons) cold water (add 15 ml of water as needed)

Procedure

 * 1) Combine flour and salt in medium bowl.
 * 2) Cut in vegetable shortening with a pastry blender or two knives, until mixture is crumbly.
 * 3) Sprinkle with cold water; mix just until mixture holds together.
 * 4) Shape dough into a ball; place on lightly floured surface.
 * 5) Roll out dough to 3 mm (⅛ inch) thickness.
 * 6) Line pie plate with pastry.
 * 7) Trim around perimeter for 2 cm (1 inch) overhang to fold under and crimp as desired (see pie crust edges below).

Simple Fork Edge

 * 1) Fold overhang under and press down with your fingers.
 * 2) Using the tines of a lightly floured fork, press the edge of the pastry to the rim of the pie pan.

Fluted Edge

 * 1) Fold overhang under and pinch to make the edge stand up.
 * 2) With the thumb and forefinger of one hand, pinch the outside edge of the pastry, while pressing from the inside with the forefinger of your other hand.

Rope Edge

 * 1) Fold overhang under and pinch to make the edge stand up.
 * 2) Press the pastry along the edge of the pie plate between the side of your thumb at an angle, pinch and slightly twist.

Notes, tips, and variations

 * To make two crusts, double all ingredients, follow procedure above, and divide dough in half.
 * Be sure to use cold water and keep well wrapped until use.

title: Cookbook:Homemade Pie Crust


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The Computer Revolution/E commerce/job hunting

E-commerce is basically doing business activities online, and what would a business be without employees to assist them? Many employers are turning to online help such as Monster.com. Even the United States government has the site http://usajobs.opm.gov where future employees can apply for the job they wish in the office of the United States government. Job sites can help you find your ideal job and online resume sites can help you fix your resme to be more appealing to the employer. Now employers don't have to hire who is in their area, but can also look for people around the world who have the proper knowledge and fly them in to work for them.

∼How to look for a job online.

First, you need to make sure that you have an updated resume, so you can post it on these Websites for employers to look at. There are many Websites that can help you create a resume and give out excellent ideas.

To look for jobs on www.monster.com you first need to create and account with them. Once you do that, they actually create a mini resume for you by asking a few questions about you and your previous and/or current employment. By answering all the questions you create your profile which can be viewed by people who would be interested in hiring you. Once you are done with that they ask you to upload your resume. When the process is done, Monster will post your resume in the job portal and you will receive e-mails with people asking you to interviews.

Source: www.monster.com


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The Computer Revolution/Networks/Digital and Analog Cell Phones

Digital Cellphones
"Digital cell phones are the second generation (2G) of cellular technology. They use the same radio technology as analog phones, but they use it in a different way. Analog systems do not fully utilize the signal between the phone and the cellular network -- analog signals cannot be compressed and manipulated as easily as a true digital signal. This is the reason why many cable companies are switching to digital -- so they can fit more channels within a given bandwidth. It is amazing how much more efficient digital systems can be. Digital phones convert your voice into binary information (1s and 0s) and then compress it (see How Analog-Digital Recording Works for details on the conversion process). This compression allows between three and 10 digital cell-phone calls to occupy the space of a single analog call.

Many digital cellular systems rely on frequency-shift keying (FSK) to send data back and forth over AMPS. FSK uses two frequencies, one for 1s and the other for 0s, alternating rapidly between the two to send digital information between the cell tower and the phone. Clever modulation and encoding schemes are required to convert the analog information to digital, compress it and convert it back again while maintaining an acceptable level of voice quality. All of this means that digital cell phones have to contain a lot of processing power."

retrieved from http://electronics.howstuffworks.com/cell-phone5.htm on Feb 27, 2007

Digital cellphones can run on 4 different networks and they are: TDMA, FDMA, GSM, CDMA and how they work can be found from this link http://electronics.howstuffworks.com/cell-phone7.htm.

The digital phone has revolutionized from second generation (2G) to (2.5) and to what is now the third generation (3G) of digital technology. These 3G digital phones possess greater capabilities and increased speed to handle new features such as video, gaming and internet connection.

Advantages of Digital Cell Phones

 * better quality of sound and service
 * more security, eavesdropping protection
 * ability to support next generation services
 * stronger battery life
 * more resistant to noise
 * increased capacity

Analog Cellphones
Analog was the first technology used in cell phones and uses a range of frequencies, 832; two frequencies made up a channel. 30kHz was determined to be the width of the analog voice channel because it provided the closest quality to that of a landline. Each carrier has 395 voice channels and 21 data channels. While innovative at the time they are accompanied by numerous disadvantages. The battery life and talk time is short, they are more susceptible to dropped calls and interference due to outside noise, analog is unable to provide much of the multimedia characteristics of digital phones and they require larger sources of power and therefore have a high frequency of interacting and disrupting medical devices. One of the positives of analog technology is that the coverage is superior to that of digital, in the US 95% of the country is compatible with analog. As digital cell phone technology increases, analog will become extinct due to every disadvantage of analog being solved through digital with few new draw backs.


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The Computer Revolution/Networks/Short Range Wireless for Automation Networks

Home Automation Networks is what connects everything around a house. It connects them through switches and senors. It used a narrowband wireless technology which can operate between 100 and 250 feet. It is low powered and receives data slowly as compared to Personal Area Networks. it receives about 13.1-238 kilobits pers second. There are 3 current standards. They are Insteon, ZigBee and Z-Wave. These are referred to as "mesh technologies". Mesh Technologies are networked devices with two way radios so that they can communicate with each other with more than just the controller. It is the central command for the network. Insteon is a standard that incorporates wireless technology in with an electric power line. This is capable of sending up to 13.1 kilobits at a range of 150 feet. As the CEO describes, "drive up to your house, the garage door device recognizes yor car, and open to let you in. The lights come on and your favorite radio station starts playing." Insteon has replaced a older automation technology that was known as X10. ZigBee does not incorporate electric power lines into its technology therefore it is all wireless. ZigBee is very efficient, it can send up to 128 kilobits at a range of 250 feet. It is expected to be seen every from smoke detectors in your house to medical sensing devices. The best part is that it can function for a long time, on inexpensive batteries. Z-Wave also consists solely of wireless technology which is power efficient. It can send about 127 kilobits per second to a range of 100 feet. When you compare you would notice that Z-Wave and Insteon are very much similar. The only difference is that Insteon used electric power cables and Z-Wave doesn't.


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Cookbook:Pie Crust Edges

The edges of pie crusts may be shaped in a variety of ways for an attractive finish.

Simple Fork Edge

 * 1) Fold overhang under and press down with your fingers.
 * 2) Using the tines of a lightly floured fork, press the edge of the pastry to the rim of the pie pan.

Fluted Edge

 * 1) Fold overhang under and pinch to make the edge stand up.
 * 2) With the thumb and forefinger of one hand, pinch the outside edge of the pastry, while pressing from the inside with the forefinger of your other hand.

Rope Edge

 * 1) Fold overhang under and pinch to make the edge stand up.
 * 2) Press the pastry along the edge of the pie plate between the side of your thumb at an angle, pinch and slightly twist.

title: Cookbook:Pie Crust Edges


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The Computer Revolution/Networks/Wi-Fi

This alliance has been created in 1999 to try to create one world wide acceptable standard for high speed networking. So far there is about 250 members and it is growing every day. W-Fi is meant to be used with any network that is 802.11.

These Wi-Fi products are tested and approved by the Wi-Fi trademark. It means that any of the devices that are certified by Wi-Fi are capable to work with each other. Even if the two products are made by different manufacturers. The organization is helping other developers with information on acceptable standards for today’s world network. Some of the well known current members are Nintendo, HP, US robotics, BenQ, Alpine, Lexmark, Sharp, AT&T, and many more.

Wi-Fi Hotspots
Wi-Fi Hotspots are establishments that offer access to the Internet via a wireless LAN network. These places allow you to access the Internet on your portable device; sometimes you will be prompted with an online agreement before using the Wi-Fi. The Wi-Fi is usually used within the facility since the range is limited; once you leave the facility you lose the Wi-Fi connection.

Many public places today offer these Wi-Fi Hotspots such as: coffee shops, restaurants, waiting rooms, libraries, and many more public places. Establishments are starting to offer Wi-Fi Hotspots more-and-more. Though it is not meant to be a primary source of Internet; it is great to use when you stop somewhere for a short time.

Piggybacking on Wi-Fi access points is the practice of establishing an internet connection by using somebody other than your own Wi-Fi connection with out the direct consent of the other party. It is very controversial and laws vary depending on where it is being done. There are many motives for people wanting to “piggyback” off a connection. The motives vary but the main reason is the cost of internet for some people is too much. Although no harm is meant by most individuals who perform this act, others use “piggyback” to perform illegal activities such as identity theft, child pornography, and illegal downloads. http://www.nytimes.com/2006/03/05/technology/05wireless.html?pagewanted=all

Personal Wi-Fi Hotspots
Most of the newest phones on the market today have internet access. When you set up service, you pay not only for your telephone plan, but also a data plan as well. This data plan allows you to use your phone to surf the web, send emails, watch videos on Netflix, and most any other web based task you can think of. But what if you are going on vacation? Of course you bring your phone and your laptop. Now assume that you don’t have a data plan for your laptop (why would you after all). Instead of surfing the net on your nice big 15” laptop screen, you are stuck watching your tiny phone screen. Wouldn’t it be great if there was a way to share your data plan between the two devices? Well there is. Most mobile carriers (e.g. AT&T and Verizon) offer the capability to use a Personal Mobile Hotspot. You basically turn your phone into a WiFi access point so that you can connect your laptop, or iPad, or any WiFi capable gadget to the internet. You can also purchase a special gadget to provide the hotspot (e.g. Verizon’s MiFi device) instead of using your phone. Of course the carriers will normally charge extra for this feature, but the incremental cost is usually less than setting up a new data plan for each device.

Wi-Fi SD Cards
A convenient new technology that has become available recently is the Wi-Fi SD card. An example is the brand Eye-Fi. Eye-Fi SD cards were the first memory card to automatically upload videos and photos using Wi-Fi. The Wi-Fi SD card not only works with your camera and stores media, but the built-in Wi-Fi lets you instantly send photos to your computer, smartphone, or other device. There is also the security of knowing your photos are safe on your home computer/online. The cards are useful in the case of personal pictures being lost through theft, damage to the card/camera, or losing the camera.

Reference: Morely, Deborah; Parker, Charles. Understanding Computers Today and Tomorrow. Course Technology, 2011, Page 282.

How Wi-Fi works
Wi-Fi uses two types of frequency carrier: a single direct-sequence area distributed spectrum radio carrier and a multi-carrier OFDM (Orthogonal Frequency Division Multiplexing) radio technology. "There are two common ways to put information in a radio wave, and you've likely run into them yourself. They are called A.M. and F.M. just like the two choices you've always known are on a radio. To understand these two ways of sending information it is important to know that radio waves, by themselves, have very regular patterns. Generally they keep the same amplitude or frequency all the time. (Amplitude is the "height" of the radio wave, frequency is how close the waves are to each other.)" [Forbus, K. and Gentner, D. 1997]. http://www.qrg.northwestern.edu/projects/vss/docs/Communications/1-how-is-data-put-on-radio-waves.html http://upload.wikimedia.org/wikipedia/en/8/81/Wi-Fi_logo.png

The speed of a Wi-Fi connection depends on many different factors. First, it can become slower if there are a lot of solid objects between the computer being used and the access point. Also, the amount of interferences can play a role in making the connection slower. For instance, baby monitors, microwaves, and other devices that operate on the same frequency can affect it. Finally, the type of hardware used may affect the connection. Wi-Fi connections are typically between 100 and 300 feet indoor and 300-900 feet outdoors. Distance can be extended using devices designed for that purpose such as antennas.

How to Protect Yourself When Using Wi-Fi
While using Wi-Fi hot spots may be convenient, you must always think about protecting your computer. Wi-Fi is less secured than a wired network. A suggestion to keep your hard drive safe is to turn off file sharing when using a Wi-Fi hotspot so no one has access to any personal information. Another idea is to turn off automatically connecting to a Wi-Fi spot on your computer, so you can choose what networks you want to join. A user should also look and see what Wi-Fi network the computer is connected to. By doing this, this ensures they are on a secured Wi-Fi and not a Wi-Fi spot that someone set up to hack into your computer.

WiMAX
WiMAX is similar to Wi-Fi, but instead WiMax is designed for a longer wireless network connection. WiMax is able to cover a certain location but coverage can extend up to six miles, it has the ability to cover a broader geographical range. The areas covered by Wi-Fi are known as Hotspots, while WiMax covered areas are called Hotzones. WiMax can provide coverage for an entire city by using WiMax towers. WiMaz utilizes radio frequencies like Wi-Fi to avoid interference. There is also a mobile version of WiMax, called Mobile WiMax. Mobile WiMax enables cellphone or portable computer users to stay connected through a wireless broadband network.

Reference: Morley, Debrah, and Charles S. Parker. Understanding Computers: Today and Tomorrow. 13th Edition. Course Technology, Cengage Learning, 2011. Print.

WiFi and Smartphones
When using your phone while it is connected to a WiFi network your mobile data plan does not get deducted. It is not possible to write the specific details for all phones, since all of them are slightly different, but here are some directions on how to connect to a WiFi network on your smartphone:

BLACKBERRY:

• Go to the Applications menu

• Click on the icon for Setup WiFi

• Click Next

• Your Blackberry will scan for networks. When the list of available networks appears click on the network you would like to connect to

• Scroll down and click Connect

• When you have successfully connected click Next and then Finish

• You can now use the web browser and access the Internet

iPhone or iPad

• Open up your "Settings" icon

• click on the Wi-Fi tab

• Turn on Wi-Fi

• Your iPhone will scan for networks. Choose which network you would like to connect to

• You can now use the web browser and access the Internet

Reference:http://www.northumbria.ac.uk/static/5007/itspdf/wireless_smartphone11.pdf

title: The Computer Revolution/Networks/Wi-Fi


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The Computer Revolution/Security/Cyber Threats

There are many threats out there. Most people believe that they are kept safe from them but however 2/3 of these people don't even have a firewall. More don't even know what a denial-of-service, a worm, a virus or a Trojan horse means. A denial-of-service attack is basically a number of requests by the computer or the network. This then overloads the network and denies legitimate users access to the network. Since most computers have a certain number of limited user requests at a given time a denial-of-service attack will inhibit them all. This kind of attack will either come from one computer or maybe even more because those computer will have been taken over as well. A worm is a program that, when is on a system, copies itself over and over again. This could cause the computer to crash. There have been many recorded worms before. Code Red, Nimda, Klez, SQL Slammer, MyDoom and Sasser. Viruses are a pain in the neck. There are "deviant" programs that store themselves on your hard drive and then cause all sorts of ruckus of your computer. They could corrupt data or literally blow up something. A way of transport of viruses are through email. The most famous was the love bug email. The subject line was "I LOVE U". It resulted in about $10 million worth of damage. Viruses can also do annoying things. Like have a pop up telling you to legalize marijuana, or have ping pong balls shooting around. It could even spread to external devices like your camera flash card and destroy it as well. Trojan Horses...Remember the story of the Trojan war? When the Greek soldiers tricked the Trojans into letting them into the grounds? Well, the Greek soldiers would be the virus. The Trojan horse would be the decoy Trojan horse that got them in. A Trojan horse is basically a carrier for viruses. It shows itself as a program that could be of great use to you. It could be a game or a screensaver but when its installed the instructions are to destroy or corrupt data on your computer. The worm, the virus and the Trojan horse are all apart of Malware. Malware is malicious software that is designed to attack a computer.

New Challenges for Cybersecurity

Many experts believe that 2012 will bring new challenges for cyber security. Security giant McAfee release a report titled ‘2012 Threat Predictions’ that detailed an expected rise in attacks against the U.S. Many of these threats are believe to be politically-motivated. There is also expected to be an increase in smartphone viruses. Panda Security predicts that foreign cyber espionage as well as social networking attacks will both contribute to a loss in government, corporate, and personal data. They believe that these data thefts should be a top security issue that organizations focus on this year. Both companies agree that Privacy violations will only increase in 2012.

Retrieved from http://cybersecuritynews.org/ on March 02, 2012.

On February 13, 2013, Representative Mike J. Rogers introduced the Cyber Intelligence Sharing and Protection Act (CISPA). This bill was design to protect or prevent cyber-attacks on the government and infrastructure. If the bill is passed, it would allow private companies to share data with law enforcement and government agencies with the hope it would help solve or prevent cyber-attacks without the need to go through legal channels. Included in the bill, immunity from legal action for the government and private companies that share data. Proponents of the bill say the wording is much too vague which allows for individual interpretation. This bill shows the delicate balance of protection vs. privacy.

http://thomas.loc.gov/cgi-bin/bdquery/z?d113:HR00624:@@@D&summ2=m&


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The Computer Revolution/Communication/How communications help with education

Computers have become an essential necessity concerning education in the today’s world. Examples of this would be the use of: power point presentations in classrooms, Blackboard, email, and editing.

May professors use power point presentations to lecture a particular class, its makes it much easier for the professor to teach a subject with power point slides.

Also, the use of the online Blackboard has enabled professors to communicate much more effectively. Students these days are enabled to complete assignments and hand them in online via Blackboard. This makes it more convenient to complete assignments from anywhere; from home, work, or even across the world. The use of email also does the same thing.

Editing assignments has become easier for students because of computers. The use of spell and grammar checkers like in Microsoft Word make editing a lot faster than before. Also, this saves paper and time. The students no longer have to print out rough copies and re-write assignment that require corrections; rather they just edit everything and print out the final copy once all the editing is completed.


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Talk:Digital Signal Processing/Bilinear Transform

Bilinear Conversion
Provided sampling rate is not far in excess of the largest frequency component, a quick term-to-term conversion can use as approximation:

$$ z-term= e^{-a*T}*[1-A*(4*a/w_s)^B]  $$

where Ws=sampling rate <Nyquist rate (rad/s) T=sampling period, sec =2PI/Ws a=s-term, real or complex 4a/Ws <=1       (A,B)=f{specific problem}

for example,(A,B)=(0.85,3.17) the s-term (s+5.0) with T=2PI/40 yields z-term (z-0.4129). Similarly, term s^2+2.31s+2.72 becomes z^2-1.64z+0.70

there are existing rules for introducing additional z-terms as needed to stabilize and improve magnitude match.

For moderate sampling rate the bilinear transform sees a divergence region for frequency response towards the Nyquist limit.

This can be improved by applying a slightly increased sampling rate up to the original Nyquist limit, at least with well conditioned transfer functions ie positive real.--Billymac00 21:05, 12 December 2006 (UTC)

Filter design
Perhaps an example could be added to illustrate how to use it? Especially the frequency prewarping technique.

Wording
"...The resulting filter will have the same characteristics of the original filter..." This is not precisely true, as the typical scenario is solid match on magnitude but not necessarily on phase unless the transfer function is positive real.--Billymac00 (discuss • contribs) 01:57, 7 January 2015 (UTC)

Al-Alaoui variant
Al-Alaoui has introduced a variant of the bilinear as follows:
 * $$s = \frac{2(z-1)}{T(z(1+q)+(1-q))}$$\where 0<=q=<1

I have not scrutinized it closely, especially for phase match... --Billymac00 (discuss • contribs) 01:48, 7 February 2015 (UTC)


text:
Talk:Blender 3D: Noob to Pro/Printable Version

Hi, does anyone know if there is any way to move the 3D cursor using the keyboard? Or is there a way to move an object relative to the center of the scene using the keyboard? I need to find out how to do one of these, because otherwise I have to leave the cursor where it started which isn't easy (sometimes I accidentally left click). After that, any objects that I create will never be an exact distance from objects created before the cursor was moved.

I don't know if you still need help but, if you press shift+C, the cursor will move to the center of the grid, or if you press shift+s, you can snap the cursor to the closest intersection on the grid. Marky1991 23:58, 3 February 2007 (UTC)


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The Computer Revolution/Peripherals/Web Cameras

A web cam is a device that usually connects to the computer via a USB port. A web cam takes what it sees in it's lens and transmits it to the computer as an image.

Now a days web cams are used for a variety of things. For example, you can chat with a friend or relative across the globe and have a video conference so you can see them and they can see you. Web cameras posses many positive and negative qualities.

History of the Web Camera
In 1991, the Web Camera was born in Cambridge University, in the Trojan room coffee pot, in the computer science department.

On this website you will see the first image of the Trojan room coffee pot that the web camera gave; as well as a detailed description of how the science department configured the camera.

Web cameras are a magnificent choice for people who want to share information via the Internet. It's main role is to show a video with sound from one computer onto another computer and vice versa with just a web camera to gather what its sharing. This allows people in any situation to converse over the web however they want. Web cameras are made in different sizes and shapes. Some web cameras are built inside a computer and some are round with a camera in the center. Any web camera, as long as its not built in can be placed anywhere and used whenever it is plugged into a system that allows web camera usage. Web camera are nothing more than a camera that can record data and send it out, while receiving it simultaneously. It also can transfer data instantly allowing multiple people to use a web camera at the same time together.

Source: http://www.experienceproject.com/dictionary/definition-of/Webcam

The Advantages of Web Cameras

 * A web cam enables individuals to monitor their home while away
 * A web cam can be used to take pictures and make videos
 * Older individuals who have difficulty leaving their home but who want to still keep in touch with their friends can use a web cam to do so
 * Hearing Impaired individuals find the web cam useful when communicating with others
 * With a web cam you can observe your babysitter's behaviour toward your child
 * Inter-office communication between cities can be set up at a reasonable cost (i.e. video-conferencing at a fraction of the price)
 * Useful for individuals who have social anxiety and don't like to meet people in person, perhaps a blind date situation
 * Communication can be ended at any time at the click of your mouse

The Disadvantages of Having a Web Cam

 * A potential invasion of privacy exists
 * Because web cams have high quality resolution and are easy to use, they can be used to exploit children through pornography
 * Web cams are movable which increases the risk for damage
 * Web cams remove the need to socialize in person creating a lack of human interaction
 * As people spend more time watching TV, surfing the internet, playing computer games, etc., the web cam is yet another health hazard

The Different Types of Web Cameras

 * IP Camera

The Price of a Web Camera
The price of a web camera varies quite a bit depending on what additional features you require in a web camera. Here are a few different web cameras on the market, note prices included are published MSRP and may vary by retailer.

--- CP Technologies USB Mini PC WEB Flex CAM - Video conferences, video mail, photos and photograms

Available Since : Feb 28, 2004 Price : $17.29

http://img.nextag.com/image/CP_Technologies_USB_Mini/1/000/000/615/716/61571661.jpg --- HP Webcam, Integrate Microphone, Plug n Play USB Conn. This can used with integrated microphones to arrange video conferencing. This product can capture large video with 640 x 480 pixels resolution; it also has a high refresh rate of 30 frames per second.

Available Since: Nov 3, 2006 Price: $39.99

http://img.nextag.com/image/HP_Webcam_Integrate_Microphone/1/000/005/272/157/527215703.jpg --- Microsoft Lifecam VX6000 USB WEB Camera - Compact camera which connects to your computer via a standard USB 2.0 interface. Allows you to participate in web conferencing, record high-resolution video to your computer and take 5 megapixel still images. An integrated microphone allows you also capture audio.

Available Since: Mar 6, 2006 Lowest Price: $75.61 ---

Web Cameras and Virtual Travel
Hey who needs to leave there homes when all they need is a computer with internet access, I've always wanted to see Halifax Nova Scotia and by clicking below you to can see it live. You have to love the internet. lol

http://www.halifaxwebcam.ca/live/


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The Computer Revolution/Security/The Evil Twin Attack

What is Evil Twin Attack?
It is an unsecured wireless network attack, which allows hackers to steal your personal information.

How the Evil Twin Attack works
For instance, let's say you arrive at your destination and you need to access the internet to check if your pay check has been processed into your account. You open your laptop and sign on to the internet not knowing that the access point is the one of the hackers. Initially you type the address of your bank website. Everything is going smoothly, and you believe that you have entered a secure website. You enter in your bank card number and your password, not realizing that the website that you are using is a fake website, which resembles the official bank website. The only difference between the websites is that the fake one is unencrypted(its open for hackers to see your secure information). This way somebody else is stealing your information without your knowledge. Hackers create an access point on any network and by doing so they are able to track your every move, they can even read your mail with you.

How to protect yourself from an Evil Twin Attack

 * Check your wireless internet setting to ensure that you are logged onto a secured connection.
 * Ensure your pop-up protection for adware is enabled.
 * When using credit cards designate one credit card for internet purposes, with a low limit.
 * Do not use public wireless connections when conducting private business.


text:
The Computer Revolution/Peripherals/Monitors

=Monitors=

CRT
CRT stands for Cathode-ray tube, this type of monitor was the most widely used until the release of LCD monitors (and TVs), the same technology employed was the same as the one used in common televisions screens. The Cathode ray projects a series of electrons onto a screen to ultimately produce an image, however the process of electrons to an image is much more tedious than a simple conversion.

CRT monitors soon became inexpensive and have been always easy to maintain, even more if compared with newer technologies. But in a competitive world, TVs and monitor had to changed over the years. Today many companies have halted their production of CRT monitor due to drastic decrease in revenue due to tighter energy standards and new competing technologies. Most companies have recorded a decrease of half of what CRT monitors used to bring. More companies are focusing on big demand of the new LCD monitors. It is a changing world and you have to change with it.

The biggest advantage of the CRT is that it is cheaper to manufacture which enables the poor countries to afford such a product the another, still unmatched, other advantages are the capacity for brightness, the color precision (CRTs still provide richer color in a fuller variety than most LCDs, here they will have a lasting niche market), a rapid refresh rate (important for fast changing graphics), an increased viewing angle (CRT provides the same brightness and color from a variety of different viewing angles), multiple resolutions and a lower purchase price.

Some negative points of CRT monitors is that they are power hungry (most was wasted as heat) and take more material to construct, they tend to be heavy and large. The CRT screen also lacked the newer technologies, glare from the surroundings could cause reflection, resulting in a poor quality for viewing.

History of the CRT
This type of monitor was possible due to a German scientist named Karl Ferdinand Braun that in 1897 invented the first cathode ray tube. Braun introduced a CRT with a fluorescent screen, known as the cathode ray oscilloscope - an oscilloscope is an electronic display device containing a cathode ray tube (CRT), used to produce visible patterns that are the graphical representations of electrical signals. The screen would emit a visible light when struck by a beam of electrons.

A Russian scientist, named Boris Rosing, in 1907 used a CRT in the receiver of a television system. Rosing also transmitted crude geometrical patterns onto the television screen and was the first inventor to do so using a CRT. The first practical signal generating tubes were invented by Vladimir K. Zworykin and Philo T. Farnsworth.

Only in the 1940’s were the first CRT produced in the form of Televisions. Even though it was developed over hundred years ago, scientists have improved its picture quality over time. But it still runs on the same basic principles. Today the way a CRT tube works seems very simple and is used still in most TV screens and, in lowering numbers, as PC monitor.

LCD
LCD or liquid crystal display screens are the newest and sharpest screens. Even though the use of LCD screens have been around for a long time, the technology has only been recently incorporated into the use of both televisions and computer monitors. The LCD screen uses rare characteristics that make it much more appealing than conventional CRT monitors. One of the key characteristics of LCD screens are the size advantage compared to a conventional CRT screen, a LCD screen does not employ the use of a cathode ray. But instead layers of filters and glass which polarize light and project onto liquid crystals which reveal sharp quality and excellent detail of the picture. Another interesting aspect of LCD screens is that there is almost no reflection of light from the surroundings into the screen.

Other Advantages of the LCD Monitors

 * Brightness- the LCD monitor has a brightness of 250 to 300 nits
 * No flicker- there is no flicker on a LCD, because it has a constant source of light over the whole screen
 * Power consumption- consumes less power than the CRT, approximately one-third
 * Ergonomics- the dimensions and the weight of the LCD permit it to consume less space. Example: mounting it on a wall
 * Low emissions- LCDs cause no electromagnetic interference

Disadvantages of the LCD Monitor

 * Blurry images outside native resolution
 * Motion blur on fast moving images
 * Some models have reduced color clarity    Samsung Galaxy Tab Japanese edition.jpg

Plasma Displays
Plasma displays are a type of flat-panel display. They have a comparable look to LCD displays and also use layered technology. However, instead of using liquid crystals like the LCD, plasma displays utilize a layer of gas between two glass plates. In plasma displays a phosphor-coated screen is used. Each pixel in the display is comprised of three cells encompassing the primary colors of visible light. Electronic charges are applied to make the gas atoms light up the phosphors to generate the image on the screen. In general, plasma displays tend to have a better contrast ratio, wider viewing angles, and less motion blur compared to LCD screens. On the other hand, plasmas are apt to use up greater electricity and older generation displays were more susceptible to screen burn-in and image retention.

Touch Screens
A touch screen is monitor-like peripheral that allows a user to input information into a computer without using a mouse or keyboard. Just like its name- you simply touch the screen to make a selection. Touch screens are found in a variety of places: personal computers, tablets, self-checkouts, ATMs, cell phones and even some cars. Touch screens are generally compact and can be stored in various places. Some are mounted on walls, held up by brackets or built into countertops. There are disadvantages to touch screens for people with certain disabilities. People who are blind or have limited mobility may not be able to full access and use a touch screen to the same level as others.

Electronic Paper
Have you seen the Amazon Kindle or Sony E-Reader? If you have, you’ve noticed that the screen looks almost exactly like a printed sheet of paper. That’s because these devices use electronic paper (e-paper) for their display. An electronic paper display uses a technology called electrophoretics that was developed by E Ink Corporation. The technology uses tiny charged white and black ink particles to simulate the look of paper. An applied voltage pulls either the white or black beads to the top of the screen, while the opposite beads fall to the bottom, thus giving the contrasting look of the words versus background on the screen. The technology requires much less power than other flat panel display technologies because there is no back-light needed and no power required to maintain the display, only to change the display. Devices using this technology are much easier to read in direct sunlight as well.

OLEDs
Organic light emitting diode (OLED) a type of flat-panel display that may one day replace LCD technology. OLED displays use layers of organic material which emits light when electric current is applied. OLEDs are more energy efficient than LCDs because they don’t use backlighting which also lengthens the battery life of portable devices. Other advantages of OLEDs is that they are thinner than LCDs and have a wider viewing angle, so the display is visible from all angles. Another advantage of OLEDs is that they support new technologies such as flexible OLED (FOLED) in which the display is built on a flexible surface, allowing is to roll up when the device is not in use, and transparent OLED (TOLED) where the part of the display that doesn’t have an image is totally transparent. This could open up possibilities such as the use of displays on windows, auto windshields, and other transparent items.

Digital Vs Analog
Analog and digital signals rely on two very different ways of translation. Analog is initially a digital signal that becomes translated by a graphics card into an analog signal which is then used for the display of the monitor. However the problem in this process is that quality and definition becomes “lost” in the translation from digital to analog, resulting in less sharpness and depth. Now a digital signal when properly connected to a DVI or digital video interface allows the digital signal to be directed right to monitor with no translation. DVI provides a high-speed digital interface through Transition Minimized Differential Signaling (TMDS). A transmitter on the video adapter transfers digital data to a receiver in the monitor. TMDS accepts the signal from the video adapter, determines the resolution and refresh rate that the monitor is using, and spreads the signal out over the available bandwidth to optimize the data transfer from computer to monitor. This results in a higher quality picture that appears more crisp and clean.


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The Computer Revolution/Security/Malware

Malware consists of worms, viruses and Trojan horses. The similarity between these three is that all three are aimed at attacking your PC. There are many ways in which malware is spread. Some methods include: By infected floppies or CD's, Boot-sector virus, File Virus, Multipartite virus, Macro virus, Logic bomb, Trojan horse and email hoax. The first way, an infected floppy or CD can have a virus loaded on it. This could be a prank from a friend or a repair person. A boot-sector virus is a virus that is sitting in the boot-sector of your computer. That is where all the boot up information is stored for proper boot up procedures. When it is infected with a virus, the virus delivers its own instructions and then attacks your computer freely. If any other disk or CD is put into the PC that too becomes infected. If this disk or CD are then put into another computer that computer too becomes infected. File viruses attach themselves to files that start up programs. So when the file is activated the virus then turns active and then tries to work its way into the memory and infect other files as well. Multipartite virus is a hybrid virus between a file virus and a boot-sector virus. This makes it really hard to detect. A type of multipartite virus is the polymorphic virus. Just like a human virus it can change form. This makes it really hard to be detected and also changes its own profile so any antivirus cant pick up on it. The Macro virus attaches itself to mini procedures in miniature programs, those which are found in emails or spreadsheets. These are called Macros. Until recently these files have been ignored by anti virus programs. Next we have the logic bomb. These are viruses that are programmed to go off at a certain time and date. A Trojan horse is basically a carrier for viruses. It appears to be a useful program but has viruses that are attached to it ready to attack. These are emails that have been sent to warn people about a virus. However on its way through the Internet a virus get attached to it, and with a warning saying make sure to send it to everyone you know, it causes catastrophic results.

Types of Trojan Horses
Trojan Horses cannot replicate themselves like viruses and worms. There are seven main types of Trojan Horses:

1.	Remote Access Trojan (RAT): They can be downloaded from small files such as free software, games, or electronic greeting cards. Once downloaded, the intruder can gain complete administrative control of the computer gaining knowledge of every key stroke made; which can include sensitive personal information of the user.

2.	 Data Sending Trojan: Relays sensitive information back to the intruder, such as credit card information, email addresses, log files, and so on. Some are used to relay information and not intended for malicious acts. Instead they are used to serve ads to the user. Hackers gain data of the user’s Web activity and site visited to serve corresponding ads to the user.

3.	Destructive Trojan: This Trojan is used to destroy data on the user’s computer.

4.	Proxy Trojan: Uses the victim's computer as a proxy server. The Hacker can then execute any illegal or malicious act from the user’s computer over the internet.

5.	FTP Trojan: Installs a File Transfer Protocol (FTP) on the user’s machine. The Trojan then opens port 21 to the attacker allowing the system to try to download and upload files from the user’s computer.

6.	Security software disabler Trojan: Designed to disable firewall and antivirus software allowing the attacker to invade the user’s computer.

7.	Denial-of-Service attack Trojan: Initially installed through a RAT Trojan. One of the more popular RATs is the SubSeven Trojan from various computers routed to the victim’s service. Affected machines are referred to as Zombies.

Mobile Malware
Malware can infect mobile phones, portable digital media players, printers, and other devices that have computing hardware and software, just as well as computers. Bluetooth devices are particularly vulnerable because they can be infected via a Bluetooth connection just by being 30 feet from a carrier of the malware.

Mobile Malware is supposed to make the phone difficult to use, by moving icons around or crashing the phone. Sometimes the malware is money-oriented and can steal credit card data located on the mobile phone. As mobile devices continue to add more and more software components, they become more vulnerable to the malware. So in the future, where most mobile phones will have become more complicated and have software components, there will be more malware attacks. The good news is that the lack of a universal operating system for mobile devices limits the amount of mobile malware currently in circulation.