Computer science

Computer science deals with the theoretical foundations of information and computation, and with practical techniques for their implementation and application. Computer science or computing science (abbreviated CS) is the study of the theoretical foundations of information and computation and of practical techniques for their implementation and application in computer systems.[1][2] Computer scientists invent algorithmic processes that create, describe, and transform information and formulate suitable abstractions to model complex systems. Computer science has many sub-fields; some, such as computational complexity theory, study the properties of computational problems, while others, such as computer graphics, emphasize the computation of specific results. Still others focus on the challenges in implementing computations. For example, programming language theory studies approaches to describe computations, while computer programming applies specific programming languages to solve specific computational problems, and human-computer interaction focuses on the challenges in making computers and computations useful, usable, and universally accessible to people. The general public sometimes confuses computer science with careers that deal with computers (such as information technology), or think that it relates to their own experience of computers, which typically involves activities such as gaming, web-browsing, and word-processing. However, the focus of computer science is more on understanding the properties of the programs used to implement software such as games and web-browsers, and using that understanding to create new programs or improve existing ones.[3] Contents 1 History 1.1 Major achievements 2 Philosophy 3 Areas of computer science 3.1 Theoretical computer science 3.1.1 Theory of computation 3.1.2 Information and coding theory 3.2 Algorithms and data structures 3.3 Programming language theory 3.4 Formal methods 3.5 Concurrent, parallel and distributed systems 3.6 Databases 3.7 Applied computer science 4 Related fields 4.1 Artificial intelligence 4.2 Computer architecture and engineering 4.3 Computational science 4.4 Information science 4.5 Software engineering 5 Education 6 See also 7 References 8 Further reading 9 External links History Main article: History of computer science The early foundations of what would become computer science predate the invention of the modern digital computer. Machines for calculating fixed numerical tasks, such as the abacus, have existed since antiquity. Wilhelm Schickard designed the first mechanical calculator in 1623, but did not complete its construction.[4] Blaise Pascal designed and constructed the first working mechanical calculator, the Pascaline, in 1642. Charles Babbage designed a difference engine and then a general-purpose Analytical Engine in Victorian times[5], for which Ada Lovelace wrote a manual. Because of this work she is regarded today as the world's first programmer.[6] Around 1900, punch-card machines[7] were introduced. However, these machines were constrained to perform a single task, or at best some subset of all possible tasks. During the 1940s, as newer and more powerful computing machines were developed, the term computer came to refer to the machines rather than their human predecessors.[8] As it became clear that computers could be used for more than just mathematical calculations, the field of computer science broadened to study computation in general. Computer science began to be established as a distinct academic discipline in the 1950s and early 1960s.[9][10] The first computer science degree program in the United States was formed at Purdue University in 1962.[11] Since practical computers became available, many applications of computing have become distinct areas of study in their own right. Although many initially believed it was impossible that computers themselves could actually be a scientific field of study, in the late fifties it gradually became accepted among the greater academic population.[12] It is the now well-known IBM brand that formed part of the computer science revolution during this time. IBM (short for International Business Machines) released the IBM 704 and later the IBM 709 computers, which were widely used during the exploration period of such devices. "Still, working with the IBM [computer] was frustrating...if you had misplaced as much as one letter in one instruction, the program would crash, and you would have to start the whole process over again".[12] During the late 1950s, the computer science discipline was very much in its developmental stages, and such issues were commonplace. Time has seen significant improvements in the usability and effectiveness of computer science technology. Modern society has seen a significant shift from computers being used solely by experts or professionals to a more widespread user base. Initially, computers were quite costly, and for their most-effective use, some degree of human aid was needed, in part by professional computer operators. However, as computers became widespread and far more affordable, less human assistance was needed, although residues of the original assistance still remained. Major achievements This section requires expansion. The German military used the Enigma machine (shown here) during World War II for communication they thought to be secret. The large-scale decryption of Enigma traffic at Bletchley Park was an important factor that contributed to Allied victory in WWII.[13] Despite its short history as a formal academic discipline, computer science has made a number of fundamental contributions to science and society. These include: The start of the "digital revolution," which includes the current Information Age and the Internet.[14] A formal definition of computation and computability, and proof that there are computationally unsolvable and intractable problems.[15] The concept of a programming language, a tool for the precise expression of methodological information at various levels of abstraction.[16] In cryptography, breaking the Enigma machine was an important factor contributing to the Allied victory in World War II.[13] Scientific computing enabled practical evaluation of processes and situations of great complexity, as well as experimentation entirely by software. It also enabled advanced study of the mind, and mapping of the human genome became possible with the Human Genome Project.[14] Distributed computing projects such as Folding@home explore protein folding. Algorithmic trading has increased the efficiency and liquidity of financial markets by using artificial intelligence, machine learning, and other statistical and numerical techniques on a large scale.[17] Image synthesis, including video by computing individual video frames.citation needed Human language processing, including practical speech-to-text conversion and automated translation of languagescitation needed Simulation of various processes, including computational fluid dynamics, physical, electrical, and electronic systems and circuits, as well as societies and social situations (notably war games) along with their habitats, among many others. Modern computers enable optimization of such designs as complete aircraft. Notable in electrical and electronic circuit design are SPICE as well as software for physical realization of new (or modified) designs. The latter includes essential design software for integrated circuits.citation needed Philosophy Main article: Philosophy of computer science Following Peter Wegner, Amnon H. Eden proposes that there are three paradigms at work in various areas of computer science:[18] a "rationalist paradigm", which treats computer science as branch of mathematics, which is prevalent in theoretical computer science, and mainly employs deductive reasoning, a "technocratic paradigm", readily identifiable with engineering approaches, most prominent in software engineering, and a "scientific paradigm", which approaches computer-related artifacts from the empirical perspective of natural sciences, and identifiable in some branches of artificial intelligence (the study of artificial life for instance). Areas of computer science As a discipline, computer science spans a range of topics from theoretical studies of algorithms and the limits of computation to the practical issues of implementing computing systems in hardware and software.[19][20] CSAB, formerly called Computing Sciences Accreditation Board – which is made up of representatives of the Association for Computing Machinery (ACM), and the IEEE Computer Society (IEEE-CS) [21] – identifies four areas that it considers crucial to the discipline of computer science: theory of computation, algorithms and data structures, programming methodology and languages, and computer elements and architecture. In addition to these four areas, CSAB also identifies fields such as software engineering, artificial intelligence, computer networking and communication, database systems, parallel computation, distributed computation, computer-human interaction, computer graphics, operating systems, and numerical and symbolic computation as being important areas of computer science.[19] Theoretical computer science Main article: Theoretical computer science The broader field of theoretical computer science encompasses both the classical theory of computation and a wide range of other topics that focus on the more abstract, logical, and mathematical aspects of computing. Mathematical logic Automata theory Number theory Graph theory Category theory Computational geometry Quantum computing theory Theory of computation Main article: Theory of computation According to Peter J. Denning, the fundamental question underlying computer science is, "What can be (efficiently) automated?"[9] The study of the theory of computation is focused on answering fundamental questions about what can be computed and what amount of resources are required to perform those computations. In an effort to answer the first question, computability theory examines which computational problems are solvable on various theoretical models of computation. The second question is addressed by computational complexity theory, which studies the time and space costs associated with different approaches to solving a multitude of computational problem. The famous "P=NP?" problem, one of the Millennium Prize Problems,[22] is an open problem in the theory of computation. P = NP ? GNITIRW-TERCES Computability theory Computational complexity theory Cryptography Information and coding theory Main articles: Information theory and Coding theory This section requires expansion. Algorithms and data structures O(n2) Analysis of algorithms Algorithms Data structures Programming language theory Main article: Programming language theory Type theory Compiler design Programming languages This section requires expansion. Formal methods Main article: Formal methods This section requires expansion. Concurrent, parallel and distributed systems This section requires expansion. Databases This section requires expansion. Applied computer science This section requires expansion. Related fields Despite its name, a significant amount of computer science does not involve the study of computers themselves. Because of this, several alternative names have been proposed. Certain departments of major universities prefer the term computing science, to emphasize precisely that difference. Danish scientist Peter Naur suggested the term datalogy, to reflect the fact that the scientific discipline revolves around data and data treatment, while not necessarily involving computers. The first scientific institution to use the term was the Department of Datalogy at the University of Copenhagen, founded in 1969, with Peter Naur being the first professor in datalogy. The term is used mainly in the Scandinavian countries. Also, in the early days of computing, a number of terms for the practitioners of the field of computing were suggested in the Communications of the ACM – turingineer, turologist, flow-charts-man, applied meta-mathematician, and applied epistemologist.[23] Three months later in the same journal, comptologist was suggested, followed next year by hypologist.[24] The term computics has also been suggested.[25] In continental Europe, names such as informatique (French), Informatik (German) or informatica (Dutch), derived from information and possibly mathematics or automatic, are more common than names derived from computer/computation. The renowned computer scientist Edsger Dijkstra stated, "Computer science is no more about computers than astronomy is about telescopes." The design and deployment of computers and computer systems is generally considered the province of disciplines other than computer science. For example, the study of computer hardware is usually considered part of computer engineering, while the study of commercial computer systems and their deployment is often called information technology or information systems. However, there has been much cross-fertilization of ideas between the various computer-related disciplines. Computer science research has also often crossed into other disciplines, such as philosophy, cognitive science, linguistics, mathematics, physics, statistics, and economics. Computer science is considered by some to have a much closer relationship with mathematics than many scientific disciplines, with some observers saying that computing is a mathematical science.[9] Early computer science was strongly influenced by the work of mathematicians such as Kurt Gödel and Alan Turing, and there continues to be a useful interchange of ideas between the two fields in areas such as mathematical logic, category theory, domain theory, and algebra. The relationship between computer science and software engineering is a contentious issue, which is further muddied by disputes over what the term "software engineering" means, and how computer science is defined. David Parnas, taking a cue from the relationship between other engineering and science disciplines, has claimed that the principal focus of computer science is studying the properties of computation in general, while the principal focus of software engineering is the design of specific computations to achieve practical goals, making the two separate but complementary disciplines.[26] The academic, political, and funding aspects of computer science tend to depend on whether a department formed with a mathematical emphasis or with an engineering emphasis. Computer science departments with a mathematics emphasis and with a numerical orientation consider alignment with computational science. Both types of departments tend to make efforts to bridge the field educationally if not across all research. Artificial intelligence Main article: Artificial intelligence This branch of computer science aims to create synthetic systems which solve computational problems, reason and/or communicate like animals and humans do. This theoretical and applied subfield requires a very rigorous and integrated expertise in multiple subject areas such as applied mathematics, logic, semiotics, electrical engineering, philosophy of mind, neurophysiology, and social intelligence which can be used to advance the field of intelligence research or be applied to other subject areas which require computational understanding and modelling such as in finance or the physical sciences. This field started in full earnest when Alan Turing, the pioneer of computer science and artificial intelligence, proposed the Turing Test for the purpose of answering the ultimate question... "Can computers think ?". Machine Learning Computer vision Image Processing Pattern Recognition Cognitive Science Data Mining Evolutionary Computation Information Retrieval Knowledge Representation Natural Language Processing Robotics Computer architecture and engineering Main articles: Computer architecture and Computer engineering Digital logic Microarchitecture Multiprocessing Operating systems Computer networks Databases Computer security Ubiquitous computing Systems architecture Compiler design Programming languages Computational science Computational science (or scientific computing) is the field of study concerned with constructing mathematical models and quantitative analysis techniques and using computers to analyse and solve scientific problems. In practical use, it is typically the application of computer simulation and other forms of computation to problems in various scientific disciplines. Numerical analysis Computational physics Computational chemistry Bioinformatics Information science Main article: Information science Information Retrieval Knowledge Representation Natural Language Processing Human–computer interaction This section requires expansion. Software engineering Main article: Software engineering This section requires expansion. Education Main article: Computer science education Some universities teach computer science as a theoretical study of computation and algorithmic reasoning. These programs often feature the theory of computation, analysis of algorithms, formal methods, concurrency theory, databases, computer graphics, and systems analysis, among others. They typically also teach computer programming, but treat it as a vessel for the support of other fields of computer science rather than a central focus of high-level study. Other colleges and universities, as well as secondary schools and vocational programs that teach computer science, emphasize the practice of advanced programming rather than the theory of algorithms and computation in their computer science curricula. Such curricula tend to focus on those skills that are important to workers entering the software industry. The process aspects of computer programming are often referred to as software engineering. Yet while computer science professions increasingly drive the U.S. economy, computer science education is absent in most American K-12 curricula. A report entitled "Running on Empty: The Failure to Teach K-12 Computer Science in the Digital Age" was released in October 2010 by Association for Computing Machinery (ACM) and Computer Science Teachers Association (CSTA), and revealed that only 14 states have adopted significant education standards for high school computer science. The report also found that only nine states count high school computer science courses as a core academic subject in their graduation requirements. In tandem with "Running on Empty," a new, non-partisan advocacy coalition--Computing in the Core (CinC)--was founded to influence federal and state policy, such as the Computer Science Education Act, which calls for grants to states to develop plans for improving computer science education and supporting computer science teachers. See also Computer science portal Book: Computer science Wikipedia Books are collections of articles that can be downloaded or ordered in print. Main article: Outline of computer science Academic genealogy of computer scientists Computer scientist Computing History of computer science Informatics List of academic computer science departments List of computer science conferences List of computer scientists List of open problems in computer science List of publications in computer science List of pioneers in computer science List of software engineering topics Philosophy of computer science Women in computing References ↑ Denning, P. J.; Comer, D. E.; Gries, D.; Mulder, M. C.; Tucker, A.; Turner, A. J.; Young, P. R. (Jan 1989). "Computing as a discipline". Communications of the ACM 32: 9. doi:10.1145/63238.63239.  "Computer science and engineering is the systematic study of algorithmic processes-their theory, analysis, design, efficiency, implementation, and application-that describe and transform information." ↑ Wegner, P. (October 13–15, 1976). "Research paradigms in computer science". Proceedings of the 2nd international Conference on Software Engineering. San Francisco, California, United States: IEEE Computer Society Press, Los Alamitos, CA. "Computer science is the study of information structures"  ↑ "Common myths and preconceptions about Cambridge Computer Science" Computer Science Department, University of Cambridge ↑ Nigel Tout (2006). "Calculator Timeline". Vintage Calculator Web Museum. http://www.vintagecalculators.com/html/calculator_time-line.html. Retrieved 2006-09-18.  ↑ "Science Museum - Introduction to Babbage". Archived from the original on 2006-09-08. http://web.archive.org/web/20060908054017/http://www.sciencemuseum.org.uk/on-line/babbage/index.asp. Retrieved 2006-09-24.  ↑ "A Selection and Adaptation From Ada's Notes found in "Ada, The Enchantress of Numbers," by Betty Alexandra Toole Ed.D. Strawberry Press, Mill Valley, CA". http://www.scottlan.edu/Lriddle/women/ada-love.htm. Retrieved 2006-05-04.  ↑ "IBM Punch Cards in the U.S. Army". http://www.pattonhq.com/ibm.html. Retrieved 2006-09-24.  ↑ The Association for Computing Machinery (ACM) was founded in 1947. ↑ 9.0 9.1 9.2 Denning, P.J. (2000). "Computer Science: The Discipline" (PDF). Encyclopedia of Computer Science. Archived from the original on 2006-05-25. http://web.archive.org/web/20060525195404/http://www.idi.ntnu.no/emner/dif8916/denning.pdf.  ↑ CAM.ac.uk ↑ Computer science pioneer Samuel D. Conte dies at 85 July 1, 2002 ↑ 12.0 12.1 Levy, Steven (1984). Hackers: Heroes of the Computer Revolution. Doubleday. ISBN 0-385-19195-2.  ↑ 13.0 13.1 David Kahn, The Codebreakers, 1967, ISBN 0-684-83130-9. ↑ 14.0 14.1 Cornell.edu ↑ Constable, R.L. (March 2000) (PDF). Computer Science: Achievements and Challenges circa 2000. http://www.cs.cornell.edu/cis-dean/bgu.pdf.  ↑ Abelson, H.; G.J. Sussman with J. Sussman (1996). Structure and Interpretation of Computer Programs (2nd ed.). MIT Press. ISBN 0-262-01153-0. "The computer revolution is a revolution in the way we think and in the way we express what we think. The essence of this change is the emergence of what might best be called procedural epistemology — the study of the structure of knowledge from an imperative point of view, as opposed to the more declarative point of view taken by classical mathematical subjects."  ↑ Black box traders are on the march The Telegraph, August 26, 2006 ↑ Eden, A. H. (2007). "Three Paradigms of Computer Science". Minds and Machines 17: 135–167. doi:10.1007/s11023-007-9060-8. http://www.eden-study.org/articles/2007/three_paradigms_of_computer_science.pdf.  ↑ 19.0 19.1 Computing Sciences Accreditation Board (28 May 1997). "Computer Science as a Profession". Archived from the original on 2008-06-17. http://web.archive.org/web/20080617030847/http://www.csab.org/comp_sci_profession.html. Retrieved 2010-05-23.  ↑ Committee on the Fundamentals of Computer Science: Challenges and Opportunities, National Research Council (2004). Computer Science: Reflections on the Field, Reflections from the Field. National Academies Press. ISBN 978-0-309-09301-9. http://www.nap.edu/catalog.php?record_id=11106#toc.  ↑ CSAB, Inc. ↑ Clay Mathematics Institute P=NP ↑ Communications of the ACM 1(4):p.6 ↑ Communications of the ACM 2(1):p.4 ↑ IEEE Computer 28(12):p.136 ↑ Parnas, D. L. (1998). Annals of Software Engineering 6: 19–37. doi:10.1023/A:1018949113292.  , p. 19: "Rather than treat software engineering as a subfield of computer science, I treat it as an element of the set, Civil Engineering, Mechanical Engineering, Chemical Engineering, Electrical Engineering, [...]" Further reading Overview Tucker, Allen B. (2004). Computer Science Handbook (2nd ed.). Chapman and Hall/CRC. ISBN 158488360X.  "Within more than 70 chapters, every one new or significantly revised, one can find any kind of information and references about computer science one can imagine. [...] all in all, there is absolute nothing about Computer Science that can not be found in the 2.5 kilogram-encyclopaedia with its 110 survey articles [...]." (Christoph Meinel, Zentralblatt MATH) Leeuwen, Jan van (1994). Handbook of Theoretical Computer Science. The MIT Press. ISBN 0262720205.  "[...] this set is the most unique and possibly the most useful to the [theoretical computer science] community, in support both of teaching and research [...]. The books can be used by anyone wanting simply to gain an understanding of one of these areas, or by someone desiring to be in research in a topic, or by instructors wishing to find timely information on a subject they are teaching outside their major areas of expertise." (Rocky Ross, SIGACT News) Ralston, Anthony; Reilly, Edwin D.; Hemmendinger, David (2000). Encyclopedia of Computer Science (4th ed.). Grove's Dictionaries. ISBN 156159248X. http://portal.acm.org/ralston.cfm.  "Since 1976, this has been the definitive reference work on computer, computing, and computer science. [...] Alphabetically arranged and classified into broad subject areas, the entries cover hardware, computer systems, information and data, software, the mathematics of computing, theory of computation, methodologies, applications, and computing milieu. The editors have done a commendable job of blending historical perspective and practical reference information. The encyclopedia remains essential for most public and academic library reference collections." (Joe Accardin, Northeastern Illinois Univ., Chicago) Selected papers Knuth, Donald E. (1996). Selected Papers on Computer Science. CSLI Publications, Cambridge University Press.  "Covering a period from 1966 to 1993, its interest lies not only in the content of each of these papers — still timely today — but also in their being put together so that ideas expressed at different times complement each other nicely." (N. Bernard, Zentralblatt MATH) Articles Peter J. Denning. Is computer science science?, Communications of the ACM, April 2005. Peter J. Denning, Great principles in computing curricula, Technical Symposium on Computer Science Education, 2004. Curriculum and classification Association for Computing Machinery. 1998 ACM Computing Classification System. 1998. Joint Task Force of Association for Computing Machinery (ACM), Association for Information Systems (AIS) and IEEE Computer Society (IEEE-CS). Computing Curricula 2005: The Overview Report. September 30, 2005. Norman Gibbs, Allen Tucker. "A model curriculum for a liberal arts degree in computer science". Communications of the ACM, Volume 29 Issue 3, March 1986. External links Find more about Computer science on Wikipedia's sister projects: Definitions from Wiktionary Images and media from Commons Learning resources from Wikiversity News stories from Wikinews Quotations from Wikiquote Source texts from Wikisource Textbooks from Wikibooks Computer science at the Open Directory Project Photographs of computer scientists (Bertrand Meyer's gallery) Bibliography and academic search engines CiteSeerx: search engine, digital library and repository for scientific and academic papers with a focus on computer and information science. DBLP Computer Science Bibliography: computer science bibliography website hosted at Universität Trier, in Germany. The Collection of Computer Science Bibliographies Webcasts Directory of free university lectures in Computer Science Collection of computer science lectures UCLA Computer Science 1 Freshman Computer Science Seminar Section 1 Berkeley Introduction to Computers v · d · eMajor fields of computer science Mathematical foundations Mathematical logic · Set theory · Number theory · Graph theory · Type theory · Category theory · Numerical analysis  · Information theory Theory of computation Automata theory · Computability theory · Computational complexity theory · Quantum computing theory Algorithms and data structures Analysis of algorithms · Algorithm design · Computational geometry Programming languages and Compilers Parsers · Interpreters · Procedural programming · Object-oriented programming · Functional programming · Logic programming · Programming paradigms Concurrent, Parallel, and Distributed systems Multiprocessing · Grid computing · Concurrency control Software engineering Requirements analysis · Software design · Computer programming · Formal methods · Software testing · Software development process System architecture Computer architecture · Computer organization · Operating systems Telecommunication & Networking Computer audio · Routing · Network topology · Cryptography Databases Database management systems · Relational databases · SQL · Transactions · Database indexes · Data mining Artificial intelligence Automated reasoning · Computational linguistics · Computer vision · Evolutionary computation · Expert systems · Machine learning · Natural language processing · Robotics Computer graphics Visualization · Computer animation · Image processing Human–computer interaction Computer accessibility · User interfaces · Wearable computing · Ubiquitous computing · Virtual reality Scientific computing Artificial life · Bioinformatics · Cognitive science · Computational chemistry · Computational neuroscience · Computational physics · Numerical algorithms · Symbolic mathematics Note: Computer science can also be split up into different topics or fields according to the ACM Computing Classification System.