25 Great Thinkers Every College Student Should Read

By Donna Scott

College is for expanding one’s intellectual horizons. Unfortunately, drinking and having fun can distract from learning about history’s great thinkers. From Mark Twain to Confucius, an educated individual should posses some knowledge of certain philosophers, artists and thinkers. Here are 25 great thinkers every college student should read, even if professors don’t assign them.

Western Philosophers

Western universities understandably tend to focus on Western philosophers and thinkers. Check out the works from these masters of Western philosophical thought.

1. Ralph Waldo Emerson: Emerson was an influential figure in the first recognized American school of philosophical thought. After marrying a wealthy widow, Emerson lived in relative comfort for most of his life, supporting other famous writes such as Henry David Thoreau.
2. John Stuart Mill: One of Britain’s most famous political philosophers, Mill was a member of Parliament who endlessly debated the nature of liberty and freedom.
3. Immanuel Kant: Kant’s work on the limitations and structure of reason shaped and influenced philosophical thought throughout the twentieth century. His "Critique of Pure Reason" remains a classic of philosophy and is taught in universities around the world.
4. Soren Kierkegaard: This Danish philosopher is one of the leading thinkers responsible for existentialism.
5. Niccolo Machiavelli: A must for aspiring politicians and wannabe despots, Machiavelli’s "The Prince" is the original guide to ruling an empire or corporate boardroom.

Eastern Thinkers

Eastern philosophies have proven influential on figures throughout history from Marco Polo to the Beatles. The sage wisdom offered by these Eastern thinkers still resonates with audiences separate by culture and time.

6. Confucius: A Chinese thinker and social philosopher, Confucius emphasized personal and institutional morality as well as justice and proper social relationships.
7. Avicenna: This Persian mathematician is perhaps one of the most widely known Muslim philosophers. His works discuss topics ranging from medical ethics to metaphysics.
8. Laozi: The philosophy espoused by this ancient Chinese philosopher eventually became the Taoist religion. Laozi has often influenced and served as inspiration for anti-authoritarian movements.
9. Siddhartha Gautama: Siddhartha was a price who gave away all his possessions to find a deeper meaning from life. After extensive fasting and meditation he achieved enlightenment becoming known as the Buddha. The teachings of this humble price have changed the course of history and philosophical thought.
10. D.T. Suzuki: One of the few modern members on this list, Suzuki is largely responsible for introducing Western audiences to Eastern religions such as Zen Buddhism.

Statesman

Polls show few people trust politicians. History tells a different story as great statesmen inspire courage and selfless action. These politicians are some of history’s great thinkers, speakers and individuals.

11. Winston Churchill: In his nation’s darkest hour, Winston Churchill served as a beacon of inspiration and support. Churchill’s writings and speeches are true testaments to the power of words.
12. Thomas Jefferson: Despite many hypocrisies from his actual life, Jefferson’s writings are beautiful tributes to the power of freedom. (Thomas Jefferson Biography)
13. Ataturk: The powerful, infamous Turkish leader responsible for ushering his nation into a modern era, Ataturk is a highly regarded figure from Muslim and Turkish history.
14. Mao Zedong: The leader of the Communist revolution in China, Chairman Mao’s impact on history is on increasing with time.
15. Nelson Mandela: After surviving 27 years as a political prisoner, Mandela became South Africa’s first black president beginning the healing process from decades of apartheid.

Writers and Artists

The creative representation of life presented by artists can be more truthful than anything presented by real life. These master writers and artists use characters, brilliant technique and artistic vision to boldly explore timeless questions.

16. Mark Twain: A genuinely clever wit, Mark Twain is best known for penning the classic, "The Adventures of Huckleberry Finn." Go beyond Twain’s best known works to discover a thinker centuries ahead of his Victorian time.  (Mark Twain Biography)
17. George Orwell: Modern audiences are often frightened by the remarkable foresight Orwell demonstrates in his writing. Indispensible phrases such as "big brother" and "doublespeak" were created by Orwell and are perfectly suited to modern society.
18. Gabriel Garcia Marquez: This Colombian writer focuses on themes of third world poverty and fantasy. His work is often based in history with elements of the fantastic brilliantly incorporated in the story telling.
19. Albert Camus: This French author brilliantly executed complicated existential philosophies into compelling narratives.
20. Khalil Gibran: This Lebanese philosopher, writer and painter was educated in the US before returning to his native land. Gibran’s 1923 book, "The Prophet" was extremely influential on 1960s counterculture. (yes it was)
21. Kurt Vonnegut: Zany, sharp and always funny, Vonnegut was one of the truly great science fiction writers of the 20th century. Even better, his works are extremely accessible and easy to read despite being a little whacky.
22. Gunter Grass: A German writer who won the 1999 Noble prize for literature, Grass writes literature exploring complex moral issues.
23. Marcel Proust: A brilliant French novelist, Proust’s most famous work contains over 2,000 characters over some 3,000 pages. No one could blame you for skimming the volume but the words from this genius are worth enduring.
24. Issac Asimov: One of the reasons for the popularity of science fiction during the 20th century, Asimov is best known for writing the "I, Robot" series.
25. Arthur Rimbaud: Rimbaud was a French philosopher that influenced the Beat Generation of American writers such as Jack Kerouac and Allen Ginsberg. Something of a prodigy, Rimbaud produced his best known works in his late teens before giving up writing all together at 21.

Citation

Everything Is Miscellaneous

Libraries sans Dewey

October 2nd, 2009 by davidw

Barbara Fister has a terrific article in Library Journal about libraries who have moved away from the Dewey Decimal Classification (DDC) system, many in favor of some version of the BISAC system that arranges books alphabetically by topic. This is a more bookstore-like approach. The article presents the multiple sides of this discussion, with lots of examples.
The disagreement among librarians is, to my mind, itself evidence that there is no one right way to organize physical objects. Classification is pragmatic. You classify in a way that works, but what works depends upon what you’re trying to do. Libraries serve multiple purposes, so librarians have to make hard decisions. If the DDC isn’t the safe and obvious choice, then libraries have to confront the question of their mission. The classification question quickly becomes existential in the JP Sartre sense.
At the end, she quotes from Everything Is Miscellaneous where I say that the Dewey system “can’t be fixed.” I still think that’s right in its context: No single classification system can work for everyone or for every purpose, although they can be better or worse at what they’re trying to do. In that sense, the DDC can be improved, and the OCLC has continuously improved it. But because it’s premised on assigning a single main category to each book, it is repeating the limitations of the physical world that require physical books each to go on a single shelf. Any single classification is going to be inapt for some purposes, and is going to embody biases constitutive of its culture. It’s the job of a library and of a book store to decide which single way of classifying works best for its patrons, with the obvious recognition that no single way works best for all. Books are miscellaneous. Libraries, bookstores, and the shelves over your desk are not.

http://www.everythingismiscellaneous.com/

Dewey in a different class

By Barbara Fister -- Library Journal, 10/1/2009

Not long ago, a mother blogged about her visit to a newly opened public library in Darien, CT. Though she appreciated its soaring ceilings, the fireplaces and cozy nooks, the presence of a café, and state-of-the-art technology, what really excited her was the way the books were organized. “The books everywhere, but especially in the children's room, have been shelved, labeled, and organized in a way that makes me feel less like a moron and more empowered to find what I'm looking for on my own.” She went on to say, “the Library, which in my mind used to be a little intimidating and kind of like a disapproving Mother, is reaching out to ME. 'Library' is saying to ME that she wants to be like ME and doesn't expect me to be like her anymore.”
It's not often that patrons express such strong enthusiasm for shelving systems, but in recent years librarians have been embroiled in a classification struggle. The first skirmish occurred in Maricopa County, AZ, when the new Perry Branch Library, Gilbert, opened in 2007 with nonfiction books shelved using a system adapted from the book industry, BISAC (Book Industry Standards and Communications). Unlike Dewey, which categorizes related knowledge systematically, BISAC is an alphabetical list of categories ranging from Antiques and Collectibles to True Crime. Many librarians feel BISAC's relative simplicity and user-friendly language have an advantage over Dewey's complexity.
Self-sufficiency
The BISAC system is maintained by the Book Industry Study Group, which classifies books into 52 broad categories, each with additional levels of specificity. Categories for a book are typically determined by the publisher (a job that often falls to the editor, who knows the book best) and are used throughout the distribution chain by companies like Amazon, Baker & Taylor, Barnes & Noble, Bookscan, Bowker, Ingram, and others. In many ways, it fuses the functions of subject headings with classification. Many bookstores work with the categories to organize their shelves, but the categories and subcategories are also used to create a searchable record of a book. Though the bookseller might decide to shelve the book in one category, that book may have multiple BISAC headings assigned to it in the computer system. Unlike library classification systems, BISAC codes are invisible to the end user, enabling browsing but usually requiring customers to turn to a staffer to locate a specific title.
According to Marshall Shore, a consultant who was at the Maricopa County Library District (MCLD) at the time and played a major role in inspiring the Perry Branch Rebellion, the issue isn't which system is superior; it's about the user's experience. When interviewing nonusers, he reports, “I heard over and over 'those numbers scare me,' 'I don't understand them,' 'they make me feel stupid.' The goal of having a BISAC-based scheme is to put customers at ease and help them become more self-sufficient and comfortable using the library.”
Jennifer Miele, Perry Branch manager, says the change was prompted by annual surveys. “Over 75 percent of our customers stated that they go to the library to 'browse' for materials.” Serving the fifth fastest growing community in the country, the new branch has been so popular that MCLD plans to adopt BISAC classification in all new branches and will convert existing branches as funds permit. At the Perry Branch, circulation continues to rise. According to Miele, for FY07/08, “our average circulation was 28,693 and for [FY08/09], our average was 39,693.”
“Ease, comfort, and flexibility were important parts of the planning discussion, with taxonomy being one piece,” says Shore. “The library was designed to be customer-centric.” That emphasis included placing low shelving at the entrance to draw people into the collection, tripling the number of lounge chairs, creating reading nooks, and adding signage to help patrons navigate. Shore recalls, “On opening day, extra staff were called in to handle the presumed customer confusion. I remember approaching a woman to explain the library, when she mouthed 'gardening' and made a beeline to the area, browsed, and left with a stack of books.”
Since the Perry Branch opened, four more libraries in the Maricopa system have gone Dewey-less, with a goal of ditching Dewey in all 18 system libraries.
The rebellion catches on
The innovations at MCLD have inspired other libraries. After attending a presentation about the system's experience at the Public Library Association national conference in 2008, librarians at the Frankfort Public Library District, IL, immediately began planning a conversion. According to their Freeing Dewey blog, they are “not necessarily saying no to Dewey but, rather, slowly freeing him, something that we, as well as other libraries, had begun to do years ago with our biography and fiction collections.” They chronicled their progress on Twitter, finally posting on September 10 that “our Adults Colls r officially DEWEY FREE.”
Following a visit to the Perry Branch, librarians at the Rangeview Library District, Northglenn, CO, decided to join the revolution and in 2009 became the first library system to adopt a BISAC-based classification for all of its libraries, though with some modifications. Their “WordThink” system shelves books using words—labeling the spine of a book with a broad category such as Art and a narrower term such as Drawing. Within those subsections, books are shelved alphabetically by title. According to Director Pam Sandlian Smith, “Customers often comment that when they visit bookstores, they can find things easily and would like that ease of use in libraries.” Though it took about 1000 hours of staff time, the changeover was well received. “The elegant simplicity of the system becomes evident immediately. People love the idea of simply finding all their favorite books together under a word heading, which is so easy to navigate,” says Smith. “Librarians have visited our library and have immediately fallen in love with this organization.”
Shelve under skeptical
When Maricopa made its move, the responses were fast and occasionally furious on library discussion lists and even on Metafilter, where a posting in 2007 about dropping Dewey attracted over 80 comments. One ongoing debate is whether turning to retail for inspiration is a betrayal of core library values. Tom Eland, a librarian at Minneapolis Community and Technical College who teaches courses on the politics of information, thinks that turning to business as a model for libraries shows an uncritical acceptance of market capitalism. “Unlike customer service, which is done by private sector corporations on behalf of the profit motive, public service to library patrons is done on behalf of the civic duty of library workers to serve the interest of citizens and residents of the community who patronize the library.” He's not surprised that libraries that drop Dewey often display materials using ideas from retailing. “Too bad for the people who are trying to do real research, or who want to explore a specific domain of knowledge by going to the shelves and browsing by classification area.”
Wayne Wiegand, professor of library and information studies and American studies at Florida State University, Tallahassee, says, “In general, bookstores do a better job of identifying newer titles relevant to their customers' interests, but that doesn't mean they understand those interests. They are mostly responding toa market demand.” While he thinks libraries should respond to what readers want rather than expecting readers to fit into the library's way of doing things, he takes a pragmatic view. “Dewey has faults but so does any other classification scheme.... To talk of changing classification systems at this time is unrealistic.”
Joan S. Mitchell, editor in chief of the Dewey Decimal Classification (DDC), is supportive of libraries that want to experiment. “I would never criticize a library for making a decision based on the needs of the population the library serves. If you have a popular collection for whichbroad English-language categories such as those used in bookstores are adequate, then perhaps such labeling works in your local setting.” However, she points out that “if you equate 'using Dewey' to a physical shelf location device, you are missing the rich layers of access.” Dewey can sort large collections into more specific groups than BISAC can. Moreover, a system that is entirely based on English words might inadvertently send the message that the public library is for English speakers only. A web site (Dewey.info) is under development that will, among other things, provide linked DDC summaries in nine languages.
What librarians think
Librarians in the field are actively trying to figure out the right balance. In August 2009, an online survey posted to blogs, Twitter, FriendFeed, and Rusa-L was taken by over 100 public librarians. Well over half said patron difficulty in finding nonfiction is related to three factors: having trouble understanding the online catalog, feeling intimidated by a classification system they don't understand well, and wanting to go straight to the right shelf without having to look anything up. Only half believe patrons find call numbers too complicated, and a third felt shelving categories don't pull together topics in the way patrons want to browse.
There was more disagreement about the best solution. Ten percent agreed with the statement that their library would be better off if Dewey was scrapped in favor of the browsing categories used in bookstores. Almost 50 percent agreed with the idea of keeping Dewey but adjusting categories and adding words to the call number. Just over a quarter thought enhancing Dewey with better signage would satisfy patrons. Ten percent affirmed the statement, “People who want to drop Dewey don't understand the nuances of classification and are throwing away something valuable and widely used just to follow a trend.” Three respondents felt there was no compelling reason to change.
Respondents expressed everything from “it's about time” [we gave up Dewey] to “It's part of the dumbing down of our society.” Others thought nothing would satisfy patrons completely: “We shelve fiction by the authors' last names, and sometimes by genre, and people still have trouble finding books.”
A number of respondents wondered if the experiment would scale well. “So far the libraries I've seen that have implemented a BISAC-like program have all been small branches,” one respondent wrote. “When you get to the larger collections with a much greater subject range, I'm not sure how well one can divide everything into a smaller group of categories.”
Of course, there are those librarians who think libraries already do it better than bookstores. “Dewey allows for a level of 'granulation' in topic areas that general subject areas such as those in bookstores cannot duplicate,” one wrote. “I find it harder to find materials in bookstores than in the library.” But others feel it's time for a change. “It's not about what I think, it's about what the patrons think,” wrote one. “And these days, I don't think Dewey translates well for many of our patrons—the majority wouldn't miss it at all as long as they could still find books on the subject they're looking for, especially if they could find it quickly and easily without assistance.”
The mashup solution
At the new Darien Library, the staff decided to work with Dewey rather than abandon it. According to Kate Sheehan, knowledge and learning services librarian, “adult nonfiction has been rearranged in what I like to call a Dewey/bookstore mashup. We wanted to retain the findability of Dewey while encouraging and enabling browsing. We clumped similar areas of Dewey together in eight broad categories, which we call glades,” a concept similar to the innovative “neighborhoods” created in Hennepin County's, MN, Brookdale Branch. “Dewey does a decent job of organizing, for example, travel books. They get broken down by region and then country, and it's pretty easy to browse and find,” says Sheehan. “However, Dewey leaves languages on the other side of the library, which doesn't help travelers who want to browse for materials for their trip. So, we put them in one section and call it Places. It's a flexible system that we're still tweaking based on patron feedback.”
How exactly does this work? “In terms of process,” Sheehan explains, “we made each glade a location in our ILS, and we bought stickers the same width as our spine labels, with the glade names. We went through the stacks in the old library and marked off ranges of Dewey by glade. Every book got a glade sticker above the call number. We changed the locations by call number.” The outliers, she adds, were problematic. “The 300s [social sciences] end up everywhere. And in every range of Dewey numbers, there were exceptions.”
In the children's section, changes were even more radical. Gretchen Hams-Caserotti, head of Darien's children's services, used the questions parents asked to drive her redesign. “The most common request we hear in a children's library is 'My son is three, and he really loves trains. Can you show us where those books are?'” she says. “The common thread is always a declaration of the child's age (or reading level) and intent or interest.” So she planned around that need, using open source software to map visually color-coded categories—such as colors, nature, or transportation—making it easier to find books by the categories that interested different age groups. Even prereading children know that books about trucks can be found in the red section, but the location of a particular book can be pinpointed through the catalog.
“If you spend an afternoon at a large bookstore,” Sheehan says, “you'll see people using it in a couple of ways. The bookstore-as-destination people come in, wander around, get a stack of books, a cup of coffee, and settle in. The grab-and-go folks take a quick look around and usually hop on a computer or ask an employee, find the item they're looking for, and leave. Dewey is great for the grab-and-goers, and we didn't want to lose that. Dewey is not so great for the destination users. Cooking is in technology. Gardening is in arts and recreation. Don't those two make more sense with each other?”
With six weeks to make the switch, it wasn't easy. In spite of the challenges, Hams-Caserotti would do it again in a heartbeat. “Since we opened in January 2009, the children's book circulation has been up about 30 percent each month and still growing as we fine-tune the collection and the room.”
Other approaches
The urge to find new ways to make it easier to discover books has spread to many libraries, including the Topeka and Shawnee County Public Library, KS, and Anna Porter Public Library (APPL), Gatlinburg, TN, which organized a preconference for the Association for Rural & Small Libraries in September, “Dewey or Not?” As APPL director Kenton Temple explains, “We did not drop Dewey. Rather, we split up and moved Dewey catalog numbers to suit an overall shelf location design. I visited 'bookstore' libraries and many bookstores to see what subjects were usually placed together since I assumed that some market research had been conducted in the book industry to place subjects where they would sell better. If necessary, Dewey numbers were reassigned to get books shelved where they would 'sell' better but not drop Dewey altogether.” Librarians wanted to retain Dewey's precision and its ability to identify a specific shelf location.
The San José Public Library, CA, has also embraced a bookstore approach, in part to handle soaring circulation and increased funding for materials but no increase in staff. One of its timesaving innovations is a “direct shelving method” that eliminates steps in getting books back to the stacks. Books are roughly sorted from book drops right onto trucks. Lorraine Oback, director of marketing communications for the library, estimates that more than half of the books checked in are never placed in precise Dewey order because they're shelved in a “Marketplace” near the library's entrance, which features new and popular materials in general categories.
Right next to MCLD, the much larger Phoenix Public Library (PPL) has taken another approach to integrating BISAC into the library. According to Ross McLachlan, deputy director of technical services, “We didn't go the route of 'let's abandon Dewey.'” Not only would it be too costly, but Dewey is useful. “It is a living thing. There are constant changes, always attempting to be relevant to the development of human knowledge.” To complement the traditional “shelf location with a system behind it,” PPL decided to use BISAC to enrich the catalog with additional metadata and faceted browsing.
In 2005, PPL was the second in the nation after North Carolina State University, Raleigh, to choose Endeca as a replacement for its OPAC. By working with OCLC and vendors, BISAC headings were imported into MARC records. BISAC levels of specificity complement Library of Congress Subject Headings, allowing patrons to drill down into a topic in an intuitive system of guided navigation.
Though adding BISAC headings to the catalog was labor-intensive, it should be easier for libraries in future. According to DDC's Mitchell, “We have a mapping under way between BISAC and Dewey to support the association of Dewey numbers with metadata early in the publication stream.”
On the far end of the innovation spectrum, an experiment has begun at LibraryThing to build a new system from the ground up. The Open Shelves Classification project aims to create “a free, 'humble,' modern, open-source, crowd-sourced replacement for the Dewey Decimal System.” (Both Dewey and BISAC are licensed proprietary products.) As of this writing, the project seems to have hit the pause button, but the online discussion demonstrates the conceptual and practical difficulties involved in designing a classification system.
How broken is it?
There is no doubt the library world is in a dilemma about Dewey, but the system is hardly dead. In his 2007 book, Everything Is Miscellaneous, David Weinberger said bluntly, “It can't be fixed.” In spite of that, Dewey is currently the most widely used classification system in the world, employed in 138 countries by over 200,000 libraries. But the Perry Branch Rebellion and experiments in serving both browsers and “grab-and-go” patrons have spurred a spirited discussion of how to make a singular knowledge system work in a world full of miscellany.

Barbara Fister, LJ Academic Newswire's Peer to Peer Review columnist, is a librarian at Gustavus Adolphus College, St. Peter, MN, a contributor to ACRLog, and an author of crime fiction. Her next mystery, Through the Cracks, will be published by Minotaur Books in 2010
 
From: http://www.libraryjournal.com/article/CA6698264.html

Sequential and Binary Searches

Steven S. Skiena

Sequential Search
The simplest algorithm to search a dictionary for a given key is to test successively against each element.
This works correctly regardless of the order of the elements in the list. However, in the worst case all elements might have to be tested.

Procedure Search(head:pointer, key:item):pointer;
Var
   p:pointer;
   found:boolean;
Begin
   found:=false;
   p:=head;
   While (p # NIL) AND (not found) Do
    Begin
       If (p^.info = key) then 
          found = true;
       Else
          p = p^.next;
   End;
   return p;
END;

With and Without Sentinels
A sentinel is a value placed at the end of an array to insure that the normal case of searching returns something even if the item is not found. It is a way to simplify coding by eliminating the special case.

MODULE LinearSearch EXPORTS Main;  (*1.12.94. LB*)
(* Linear search without a sentinel *)

  ...

  i:= FIRST(a);
  WHILE (i <= last) AND NOT Text.Equal(a[i], x) DO INC(i) END;

  IF i > last THEN
    SIO.PutText("NOT found");
  ELSE
    SIO.PutText("Found at position: ");
    SIO.PutInt(i)
  END; (*IF i > last*)
  SIO.Nl();
END LinearSearch.

The sentinel insures that the search will eventually succeed:

MODULE SentinelSearch EXPORTS Main;      (*27.10.93. LB*)
(* Linear search with sentinel. *)

...

(* Do search *)
  a[LAST(a)]:= x; (*sentinel at position N+1*)
  i:= FIRST(a);
  WHILE x # a[i] DO INC(i) END;

(* Output result *)
  IF i = LAST(a) THEN
    SIO.PutText("NOT found");
  ELSE
    SIO.PutText("Found at position: "); SIO.PutInt(i)
  END;
  SIO.Nl();
 END SentinelSearch.

Weighted Sequential Search
Sometimes sequential search is not a bad algorithm, especially when the list isn't long. After all, sequential search is easier to implement than binary search, and does not require the list to be sorted.
However, if we are going to do a sequential search, what order do we want the elements? Sorted order in a linked list doesn't really help, except maybe to help us stop early if the item isn't in the list.
Suppose you were organizing your personal phone book for sequential search. You would want your most frequently called friends to be at the front: In sequential search, you want the keys ordered by frequency of use!
Why? If is the probability of searching for the ith key, which is a distance from the front, the expected search time is

which is minimized by placing the list in decreasing probability of access order.
For the list (Cheryl,0.4), (Lisa,0.25), (Lori,0.2), (Lauren,0.15), the expected search time is:


If access probability had been uniform, the expected search time would have been


So I win using this order, and win even more if the access probabilities are furthered skewed.
But how do I find the probabilities?
Self-Organizing Lists
Since it is often impractical to compute usage frequencies, and because usage frequencies often change in the middle of a program (locality), we would like our data structure to automatically adjust to the distribution.
Such data structures are called self-organizing.
The idea is to use a heuristic to move an element forward in the list whenever it is accessed. There are two possibilities:

• Move forward one is the ``conservative'' approach. (1,2,3,4,5) becomes (1,2,4,3,5) after a Find(4).
• Move to front is the ``liberal'' approach. (1,2,3,4,5) becomes (4,1,2,3,5) after a Find(4).

Which Heuristic is Better?
Move-forward-one can get caught in traps which won't fool move-to-front:
For list (1,2,3,4,5,6,7,8), the queries Find(8), Find(7), Find(8), Find(7), ... will search the entire list every time. With move-to-front, it averages only two comparisons per query!
In fact, it can be shown that the total search time with move-to-front is never more than twice the time if you knew the actual probabilities in advance!!
We will see self-organization again later in the semester when we talk about splay trees.
Let's Play 20 Questions!

1.                       11.
2.                       12.
3.                       13.
4.                       14.
5.                       15.
6.                       16.
7.                       17.
8.                       18.
9.                       19.
10.                      20.

Binary Search
Binary Search is an incredibly powerful technique for searching an ordered list. It is familiar to everyone who uses a telephone book!
The basic algorithm is to find the middle element of the list, compare it against the key, decide which half of the list must contain the key, and repeat with that half.
Two requirements to support binary search:

• Random access of the list elements, so we need arrays instead of linked lists.
• The array must contain elements in sorted order by the search key.

Why Do Twenty Questions Suffice?
With one question, I can distinguish between two words: A and B; ``Is the key ?''
With two questions, I can distinguish between four words: A,B,C,D; ``Is the ?''
Each question I ask em doubles the number of words I can search in my dictionary.
, which is much larger than any portable dictionary!
Thus I could waste my first two questions because .
Exponents and Logs
Recall the definitions of exponent and logarithm from high school:



Thus exponentiation and logarithms are inverse functions, since .
Note that the logarithm of a big number is a much smaller number.
Thus the number of questions we must ask is the base two logarithm of the size of the dictionary.



Implementing Binary Search
Although the algorithm is simple to describe informally, it is tricky to produce a working binary search function. The first published binary search algorithm appeared in 1946, but the first correct published program appeared in 1962!
The difficulty is maintaining the following two invariants with each iteration:

• The key must always remain between the low and high indices.
• The low or high indice must advance each iteration.

The boundary cases are very tricky: zero elements left, one elements left, two elements left, and an even or odd number of elements!
Versions of Binary Search
There are at least two different versions of binary search, depending upon whether we want to test for equality at each query or only at the end.
For the later, suppose we want to search for ``k'':

iteration  bottom top      mid
---------------------------------------
1          2      14       (1+14)/2=7
2          1      7        (1+7)/2=4
3          5      7        (5+7)/2=6
4          6      7        (7+7)/2=7

Since , 7 is the right spot. However, we must now test if entry[7]='k'. If not, the item isn't in the array.

Alternately, we can test for equality at each comparison. Suppose we search for ``c'':

iteration  bottom  top  mid
------------------------------------
1          1       14   (1+14)/2 = 7
2          1       6    (1+6)/2 = 3
3          1       2    (1+2)/2 = 1
4          2       2    (2+2)/2 = 2

Now it will be found!
Recursive Binary Search Implementation

PROCEDURE Search( READONLY array: ARRAY [0 .. MaxInd - 1] OF INTEGER;
                  left, right: [0 .. MaxInd - 1];
                  argument: INTEGER): [0..MaxInd] =
  (*Implements binary search in an array*)
  VAR 
    middle := left + (right - left) DIV 2;
    
  BEGIN (* binary search *)
    IF argument = array[middle] THEN      (*found*)
      RETURN middle                 
    ELSIF argument < array[middle] THEN   (*search in left half*)
      IF left < middle THEN
        RETURN Search(array, left, middle - 1, argument)
      ELSE                                (*left boundary reaches middle: not found*)
        RETURN MaxInd              
      END (*IF left < middle*)
    ELSE                                  (*search in right half*)
      IF middle < right THEN
        RETURN Search(array, middle + 1, right, argument)
      ELSE                                (*middle reaches right boundary: not found*)
        RETURN MaxInd 
      END (*IF middle < right*)
    END (*IF argument = array[middle]*)
  END Search;

From: http://www.cs.sunysb.edu/~skiena/214/lectures/lect19/lect19.html 

40-year Labor of Love

Historical Thesaurus of the Oxford English Dictionary
With Additional Material from A Thesaurus of Old English
Edited by Christian Kay, Jane Roberts, Michael Samuels and Irene Wotherspoon

ISBN13: 9780199208999
ISBN10: 0199208999
Hardback, 3952 pages
Price:  $395.00

More Information here:  http://www.worldwidewords.org/reviews/re-his1.htm

Description

A 40-year project in the making, the Historical Thesaurus of the Oxford English Dictionary is the first historical thesaurus to include almost the entire vocabulary of English, from Old English to the present day. Conceived and compiled by the Department of English Language of the University of Glasgow, the Historical Thesaurus of the Oxford English Dictionary is a groundbreaking analysis of the historical inventory of English, allowing users to find words connected in meaning throughout the history of the language.

· The largest thesaurus resource in the world, covering more than 920,000 words and meanings, based on the Oxford English Dictionary 
· The very first historical thesaurus to be compiled for any of the world's languages
· Synonyms listed with dates of first recorded use in English, in chronological order, with earliest synonyms first
· For obsolete words, the Thesaurus also includes last recorded use of word
· Uses a specially devised thematic system of classification
· Comprehensive index enables complete cross-referencing of nearly one million words and meanings
· Contains a comprehensive sense inventory of Old English
· Includes a free fold-out color chart which shows the top levels of the classification structure
· Made up of two volumes: The main text, comprising numbers sections for semantic categories, and the index, comprising a full A-Z look up of nearly one million lexical items

The Historical Thesaurus of the Oxford English Dictionary is a unique resource for word-lovers of all types-linguists and language specialists, historians, literary commentators, among others-as well as being a fascinating resource for everyone with an interest in the English language and its historical development. It is a perfect complement to the OED  itself, allowing the words in the OED  to be cross-referenced and viewed in wholly new ways. 
                                                               

 Features

• A unique thesaurus resource - the very first historical thesaurus to be compiled for any of the world's languages
• The largest thesaurus resource in the world, covering more than 920,000 words and meanings from Old English to the present day based, on the Oxford English Dictionary
• Synonyms listed with dates of first recorded use in English, in chronological order, with earliest synonyms first
• Uses a thematic system of classification, with synonyms and related words forming part of a detailed semantic hierarchy
• Comprehensive index enables complete cross-referencing of nearly one million words and meanings
• Contains a comprehensive sense inventory of Old English
• Includes a free fold-out color chart which shows the top levels of the classification structure

I never knew....................

Information Science Glossary

The big four:

taxonomy

A grouping of terms representing topics or subject categories. A taxonomy is typically structured so that its terms exhibit hierarchical relationships to one another, between broader and narrower concepts. Taxonomy structure is discussed in the NISO Z39.19 (2005) standard.

thesaurus

A thesaurus puts terms into context by defining a variety of relationships among the thesaurus terms. As with most taxonomies, thesauri define broader and narrower term relationships (hierarchical relationships). In addition, they specify related terms (associative relationships) that allow the user to identify conceptual relationships between terms in different term groupings. One more type of term relationship in thesauri is the synonym relationship or equivalence relationship, which establishes preferred and non-preferred terms. Scope notes can be attached to any term to clarify the specific meaning of the term within the thesaurus. These elements – the hierarchical, associative, and equivalence relationships and scope notes – work together to enrich a thesaurus and make it far more than a simple word list.

Thesaurus structure is dictated by national and international standards, 

such as ANSI/NISO Z39.19 and ISO 2788.

classification

Classification is the backbone of organizing fields of knowledge and indexing. Its physical counterpart is the placing of a book or journal in a single spot on a library shelf. In a computer environment, a single object can be classified in several locations with a polyhierarchical system. At the core of classification is content analysis.

ontology

Ontology is a form of classification that goes beyond the three types of term relationships described above, to indicate specific functional relationships among terms. Whereas in a taxonomy terms may be classified together as “fruit”, in an ontology the conceptual relationship may define a fruit term in different contexts such as “fruit which is used in pies”; the ontological relationship might be that the item represented by term A is "used in" the item represented by term B. Ontological relationships are inherently self-describing. Ontologies are the backbone of the semantic web, as they provide multiple links to data and therefore can support search and insightful navigation.

semantics

The study of meaning in language.

http://www.dataharmony.com/library/taxonomyGlossary.html