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Ten Computer Science Breakthroughs Dr. Raymond Greenlaw Armstrong Atlantic State University School of Computing.

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1 Ten Computer Science Breakthroughs Dr. Raymond Greenlaw Armstrong Atlantic State University School of Computing

2 Dr. Raymond Greenlaw – Armstrong Atlantic State University – School of Computing2 Outline History of Computer Science Turing Machines Moores Law Recursion NP-Completeness Personal Computers The Internet The Web High-Level Languages Handheld & Wireless Devices Human Genome Project

3 Dr. Raymond Greenlaw – Armstrong Atlantic State University – School of Computing3 History of Computer Science 1673 – Gottfried Wilhelm von Leibniz invents a machine to do multiplication 1821 – Charles Babbage builds a machine to calculate exponential functions, begins designing Analytical Engine 1832 – Ada Lovelace begins writing programs (on punch cards) for the nonexistent Analytical Engine, inventing such concepts as loops and subroutines 1935 – Alan Turing defines a model for computation

4 Dr. Raymond Greenlaw – Armstrong Atlantic State University – School of Computing4 History of Computer Science 1937 – Claude Shannon links Boolean logic to digital circuit design 1939 – Turings work plays a key role in breaking the Germans Enigma code machine 1943 – Small computers are being built in multiple countries 1950 – Turing proposes a test of machine intelligence 1956 – John McCarthy coins the term artificial intelligence

5 Dr. Raymond Greenlaw – Armstrong Atlantic State University – School of Computing5 History of Computer Science 1957 – FORTRAN is released by John Backus and the IBM team 1958 – John McCarthy invents Lisp 1959 – John Backus and Peter Naur propose the use of context-free grammars to describe programming languages 1961 – Edsger Dijkstra applies the semaphore principle used in train signaling systems to mutual exclusion in computer operations

6 Dr. Raymond Greenlaw – Armstrong Atlantic State University – School of Computing6 History of Computer Science 1962 – Donald Knuth begins work on The Art of Computer Programming 1971 – Alan Kay develops the first object- oriented programming language, Smalltalk 1971 – Stephen Cook publishes a paper on non-deterministic polynomial completeness (NP-completeness), defining a new family of problems that is not computable in a practical sense

7 Dr. Raymond Greenlaw – Armstrong Atlantic State University – School of Computing7 History of Computer Science 1973 – Leonid Levin publishes a paper identifying the class of NP-complete problems independently of Cook (research was conducted in 1971) 1977 – Leslie Lamport defines a model of time for distributed systems based on a partial order of events 1980 – Microsoft is founded, helping to push PCs into widespread use with the public

8 Dr. Raymond Greenlaw – Armstrong Atlantic State University – School of Computing8 Turing Machines

9 Dr. Raymond Greenlaw – Armstrong Atlantic State University – School of Computing9 Turing Machines First conceived by Alan Turing in the mid- 1930s Formulated in an effort to write down in simplest terms what it means for a computation to proceed in discrete steps Very robust, and Turing believed it was the most powerful conceivable theoretical model due to its equivalence to other models of computing

10 Dr. Raymond Greenlaw – Armstrong Atlantic State University – School of Computing10 Turing Machines Simplest and most widely used theoretical models of computing Represented as a machine with –a tape consisting of admissible symbols, one to a cell (the tape alphabet) –a head that can read the current symbol, or replace it –and a finite control that can be in any one of a finite set of states Machine can also move the tape, one cell at a time, to the left or right

11 Dr. Raymond Greenlaw – Armstrong Atlantic State University – School of Computing11 Turing Machines Given a set of consecutive symbols on the tape, the machine is positioned on the first non-blank symbol and begins to process When the machine halts, whatever is on the tape is the output or result of the computation for the input Can formally be defined as a 4-tuple M M = (A, K, q0, δ), where A is the tape- alphabet, K is the finite set of states, q0 is the starting state, and δ is the transition function

12 Dr. Raymond Greenlaw – Armstrong Atlantic State University – School of Computing12 Turing Machines Bold denotes head position Old St.ReadWriteMoveNew St. s110Rs2 11R 00Rs3 01Ls4 s311R s411L 00Ls5 11L 01Rs1 StepSt.TapeStepSt.Tape 1s1110s31001 2s2010111s310010 3s201012s410011 4s3010013s410011 5s4010114s510011 6s5010115s111011 7s50101Halt 8s11101 9s21001

13 Dr. Raymond Greenlaw – Armstrong Atlantic State University – School of Computing13 Moores Law

14 Dr. Raymond Greenlaw – Armstrong Atlantic State University – School of Computing14 Moores Law Rule of thumb in the computing industry about the growth of computing power Gordon E. Moore, co-founder of Intel, stated the growth of computing power follows an empirical exponential law in an April 1965 article in Electronics Magazine Originally, he proposed a 12-month doubling, then a 24-month doubling The more it became accepted, this statement began to serve as a goal for the industry

15 Dr. Raymond Greenlaw – Armstrong Atlantic State University – School of Computing15 Moores Law The least rigorous interpretation is that computing power per unit cost will continue to grow exponentially The most rigorous interpretation states that the total number of transistors on the cheapest CPU will grow exponentially at a constant rate and that this constant rate produces a doubling every 12 (or 18 (as he is often misquoted), or 24) months Industry estimates show this will hold for several chip generations

16 Dr. Raymond Greenlaw – Armstrong Atlantic State University – School of Computing16 Moores Law At the end of the 1970s, Moore's Law became known as the limit for the number of transistors on the most complex chips However, it is also common to cite Moore's law to refer to the rapidly continuing advance in computing power per unit cost As consumer computer costs decline, it is getting more expensive for manufacturers to continue achieving Moores Law

17 Dr. Raymond Greenlaw – Armstrong Atlantic State University – School of Computing17 Recursion

18 Dr. Raymond Greenlaw – Armstrong Atlantic State University – School of Computing18 Recursion The invocation of a computation inside an identical computation that is already in progress Used by defining a base case, then defining rules to break down complex cases into simpler cases using a divide- and-conquer approach They break the problem into several subproblems that are similar to the original problem, but smaller in size

19 Dr. Raymond Greenlaw – Armstrong Atlantic State University – School of Computing19 Recursion A recursive algorithm is one that uses itself in its own definition Find the factorial of an integer: function factorial(int x) { if (x < 0) return -1; // error if (x==0) return 1; return factorial(x-1) * x } factorial(3) returns 6, which equals 3!

20 Dr. Raymond Greenlaw – Armstrong Atlantic State University – School of Computing20 NP-Completeness NP is the class of problems that can be solved on a nondeterministic Turing machine in polynomial time Complete problems are the computationally most difficult problems to solve in a given class NP-completeness problems are the most difficult problems to solve in the class NP

21 Dr. Raymond Greenlaw – Armstrong Atlantic State University – School of Computing21 NP-Completeness P is the class of problems that can be solved in polynomial time on a deterministic Turing machine The problems in P are considered feasibly solvable on personal computers It is conjectured that P NP This conjecture implies no NP-complete problem is in the class P Therefore, problems that are NP-complete are considered intractable

22 Dr. Raymond Greenlaw – Armstrong Atlantic State University – School of Computing22 NP-Completeness Examples of NP-complete problems are Satisfiability, Traveling Salesman Problem, and Graph Coloring Many polynomial time approximate algorithms have been developed for problems that are NP-complete

23 Dr. Raymond Greenlaw – Armstrong Atlantic State University – School of Computing23 NP-Completeness NP-complete NP P

24 Dr. Raymond Greenlaw – Armstrong Atlantic State University – School of Computing24 Personal Computers

25 Dr. Raymond Greenlaw – Armstrong Atlantic State University – School of Computing25 Personal Computers Mini-computers (non-mainframe) computers became popular in research labs In the mid-1970s microprocessor computers began to become popular People used these machines to experiment with programming, play games, or run office/productivity applications In 1982, the personal computer was named Times Man of the Year

26 Dr. Raymond Greenlaw – Armstrong Atlantic State University – School of Computing26 Personal Computers In the 1990s, personal processing power increased greatly This allowed computers to become more prevalent Higher-end computers are now distinguished from home computers by their reliability, as opposed to raw power Computers in every home allowed more people to get interested in programming and other aspects of computer science

27 Dr. Raymond Greenlaw – Armstrong Atlantic State University – School of Computing27 Personal Computers The term PC is often used to describe IBM compatible computers, the first batch of computers to reach consumers This term has now been expanded to include products by companies like Apple, although they prefer not to be included because of the implied relationship to IBM PCs

28 Dr. Raymond Greenlaw – Armstrong Atlantic State University – School of Computing28 The Internet

29 Dr. Raymond Greenlaw – Armstrong Atlantic State University – School of Computing29 The Internet The global system of networked computers together with their users and data 1969 – ARPANET was started by the Department of Defense to enable researchers to share super-computing power Initially only four nodes, at the University of California at Los Angeles, UC at Santa Barbara, University of Utah, and the Stanford Research Institute

30 Dr. Raymond Greenlaw – Armstrong Atlantic State University – School of Computing30 The Internet In the 1970s, ARPANET was used by the military, large companies like IBM, and universities (for email) Local Area Networks became more prevalent and an open design was proposed 1972 – Nodes existed in England, and there were a total of 23, Ray Tomlinson invented email 1976 – AT&T Bell Labs developed UNIX to UNIX CoPy (UUCP)

31 Dr. Raymond Greenlaw – Armstrong Atlantic State University – School of Computing31 The Internet 1979 – User Network (USENET) was started by using UUCP to connect Duke and the University of North Carolina at Chapel Hill which allowed newsgroups to emerge 1980 – The Computer Science Network (CSNET) connected all university Computer Science departments in the U.S. 1981 – The Because Its Time Network (BITNET) formed at the City University of New York spawning many mailing lists

32 Dr. Raymond Greenlaw – Armstrong Atlantic State University – School of Computing32 The Internet 1983 – The U.S. Defense Communications Agency requires that all ARPANET hosts use TCP/IP allowing computers to communicate easily 1985 – The National Science Foundation Network (NSFNET) connects the NSFs five supercomputing centers 1988 – The Internet Worm is released, infecting 10 percent of all Internet hosts, this same year, Internet Relay Chat is written by Jarkko Oikarinen

33 Dr. Raymond Greenlaw – Armstrong Atlantic State University – School of Computing33 The Internet 1989 – NSF takes control of ARPANET in a largely transparent move The number of hosts at this time is over 100,000 1991 – Gopher is developed at the University of Minnesota, allowing the retrieval of files on the Internet The Internet ends up spawning massive amounts of information sharing and connectivity for people spread across the country

34 Dr. Raymond Greenlaw – Armstrong Atlantic State University – School of Computing34 The Internet Current Internet stats –Hosts (July 2005): 353.3 million [1] –Users (Nov. 2005): 972.8 million [2] –Registered Domains (Dec. 2005): over 60 million active domains [3] 1.www.isc.org - Internet Service Consortium 2.www.internetworldstats.com/stats.htm - Internet World Stats 3.www.whois.sc/internet-statistics/ - Whois Source

35 Dr. Raymond Greenlaw – Armstrong Atlantic State University – School of Computing35 The Web

36 Dr. Raymond Greenlaw – Armstrong Atlantic State University – School of Computing36 The Web 1991 – Tim Berners-Lee at CERN (a French acronym for the European Laboratory for Particle Physics) invents the World Wide Web (WWW) as a simple way to publish information and make it available on the Internet 1992 –WWW becomes publicly available to the public 1993 – Mosiac, a graphical browser for the Web was released by Marc Andreessen and other graduate students at U. Illinois

37 Dr. Raymond Greenlaw – Armstrong Atlantic State University – School of Computing37 The Web 1994 – Netscape Communications, formed by Marc Andreessen and Jim Clark, releases Netscape Navigator, a Web Browser that becomes widely used 1994 – Stanford graduate students David Filo and Jerry Yang develop a search engine and directory called Yahoo! 1995 – Sun releases Java, initially for interactive Web pages 1995 – Microsoft commits many resources to Internet Explorer

38 Dr. Raymond Greenlaw – Armstrong Atlantic State University – School of Computing38 The Web 1995 – Courses about the Internet begin to be offered in colleges 1998 – Netscape releases the source code for their browser 1998 – Google, founded by Larry Page and Sergey Brin, incorporates. Started as a research project in 1996 at Stanford; steadily becomes a leader on the Web, with a revenue of over $3 billion in 2004 2005 – Google claims unique index of over 8 billion pages

39 Dr. Raymond Greenlaw – Armstrong Atlantic State University – School of Computing39 High-Level Languages

40 Dr. Raymond Greenlaw – Armstrong Atlantic State University – School of Computing40 High-Level Languages A programming language that is more user-friendly, to some extent platform- independent, and abstract from low-level computer processor operations such as memory accesses Originally, programmers only had access to machine instructions specific to the computer with which they were working This led to machine-specific code and lots of time spent learning languages that could only be used sparingly

41 Dr. Raymond Greenlaw – Armstrong Atlantic State University – School of Computing41 High-Level Languages Often has built in functions to perform tasks like input and output Contains constructs that help reduce the complexity of formulating solutions to problems Abstracts many of the ideas that need to be expressed in code This allows for code reuse and extensibility High-level languages began to come into being in the 1950s

42 Dr. Raymond Greenlaw – Armstrong Atlantic State University – School of Computing42 High-Level Languages FORTRAN was one of the first widely- adopted high-level languages, it was designed by John Backus at IBM and implemented in 1957 ALGOL 58 was invented in 1958 through international efforts 1960 – COBOL (COmmon Business Oriented Language) is introduced in 1960 1964 – BASIC (Beginner's All-purpose Symbolic Instruction Code) is implemented, originally devised by Kemenry and Kurtz

43 Dr. Raymond Greenlaw – Armstrong Atlantic State University – School of Computing43 High-Level Languages 1972 – C developed by Ken Thompson and Dennis Ritchie for use on UNIX 1983 – C++ is released by Bjarne Stroustroup as an enhancement to C, originally called C with classes 1995 – Java is made public. Developed by James Gosling and other associates at Sun; it is an object-oriented language 2000 – C# from Microsoft is developed; it is based on C++ and Java to ease developers transition

44 Dr. Raymond Greenlaw – Armstrong Atlantic State University – School of Computing44 Handheld & Wireless Devices

45 Dr. Raymond Greenlaw – Armstrong Atlantic State University – School of Computing45 Handheld & Wireless Devices With the miniaturization of components, handheld devices have become more and more ubiquitous Personal Digital Assistant (PDA) was coined by John Sculley at the Consumer Electronics Show in January 1992 Currently, the leading companies in PDAs are Palm, Microsoft, and Blackberry These devices started with small, simple applications like day planners and address books

46 Dr. Raymond Greenlaw – Armstrong Atlantic State University – School of Computing46 Handheld & Wireless Devices Sculley predicted that handheld devices would become ubiquitous tools that would hold phone numbers, calendars, notes, and send and receive data wirelessly 1993 – Apple introduces the first PDA, the Newton, which provided a small subset of the features Sculley predicted 1996 – Palm releases the PalmPilot which does everything Sculley predicted except wireless communication, would later release the Palm VII, adding wireless

47 Dr. Raymond Greenlaw – Armstrong Atlantic State University – School of Computing47 Handheld & Wireless Devices Most of these devices run off a variation of the ARM architecture Many PDAs have experienced a convergence towards mobile phones that include many of the original PDA features, but also provide phone service A big component in widespread use was the wireless capabilities that eventually reached the platform Wireless communication allows for devices to communicate over the air

48 Dr. Raymond Greenlaw – Armstrong Atlantic State University – School of Computing48 Handheld & Wireless Devices Early form of wireless communication was over IR (infrared) but is now more commonly seen as Bluetooth, or other methods of short-range communication Wireless communication has allowed technology to penetrate areas where it previously couldnt be used effectively This has also allowed users to accomplish more things away from their offices and homes

49 Dr. Raymond Greenlaw – Armstrong Atlantic State University – School of Computing49 Human Genome Project

50 Dr. Raymond Greenlaw – Armstrong Atlantic State University – School of Computing50 Human Genome Project An endeavor to map the human genome down to the base pair level and to identify all genes present Launched in 1986 by Charles DeLisi Formally founded in 1990 by the U.S. Department of Energy and the U.S. National Institutes of Health, was expected to take 15 years A rough draft of the human genome was released in 2000

51 Dr. Raymond Greenlaw – Armstrong Atlantic State University – School of Computing51 Human Genome Project A private group, Celera Genomics, was also working on the project at the same time On April 14, 2003, a joint press release from both groups announced that 99% of the genome was sequenced with 99.99% accuracy The sequence of human DNA is stored in a publicly accessible database called Genbank

52 Dr. Raymond Greenlaw – Armstrong Atlantic State University – School of Computing52 Human Genome Project The HGP harnessed computing power and techniques to help accomplish their goals This project pushed bioinformatics to the forefront, a field that many believe will be where the majority of new breakthroughs will occur

53 Dr. Raymond Greenlaw – Armstrong Atlantic State University – School of Computing53 Conclusions This list is only a small sampling of breakthroughs that have contributed greatly to the field of computer science. We would like to thank the many other computer scientists who havent been recognized, but have given greatly to our pool of knowledge. The future is bright, there are many active fields of research, and we look forward to acknowledging other breakthroughs in computer science.

54 Dr. Raymond Greenlaw – Armstrong Atlantic State University – School of Computing54 References Cormen, Thomas, et. al. Introduction to Algorithms. United States: McGraw-Hill Book Company, 2001. Dewdney, A.K. The New Turing Omnibus. New York: Henry Holt and Company, 1989. Greenlaw, Raymond and Ellen Hepp. Inline/Online: Fundamentals of the Internet and the World Wide Web. United States: McGraw-Hill, 1999. Gurari, Ethan. An Introduction to The Theory of Computation. Maryland: Computer Science Press, 1989. Multiple Articles, November 2005 Shasha, Dennis Elliott. Out of their minds: the lives and discoveries of 15 great computer scientists. New York: Copernicus, 1995. Tourlakis, George J. Computability. Reston: Reston Publishing Company, Inc., 1984.


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