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Computer science



 
 
Computer science (or computing science) is the study of the theoretical foundations of information
Information

Information as a Conveyed concept has a diversity of meanings, from everyday usage to technical settings. Generally speaking, the concept of information is closely related to notions of constraint, communication, control system, data, form, instruction, knowledge, Meaning , stimulation, pattern, perception, and knowledge representation....
 and computation
Computation

Computation is a general term for any type of information processing. This includes phenomena ranging from human thinking to calculations with a more narrow meaning....
, and of practical techniques for their implementation and application in computer
Computer

A computer is a machine that manipulates Data according to a list of Code .The first devices that resemble modern computers date to the mid-20th century , although the computer concept and various machines similar to computers existed earlier....
 systems. It is frequently described as the systematic study of algorithmic
Algorithm

In mathematics, computing, linguistics and related subjects, an algorithm is a sequence of finite instructions, often used for calculation and data processing....
 processes that describe and transform information; the fundamental question underlying computer science is, "What can be (efficiently) automated?" Computer science has many sub-fields; some, such as computer graphics
Computer graphics

Computer graphics are graphics created by computers and, more generally, the representation and manipulation of pictorial data by a computer....
, emphasize the computation of specific results, while others, such as computational complexity theory
Computational complexity theory

Computational complexity theory, as a branch of the theory of computation in computer science, investigates the problems related to the Computational resource required for the execution of algorithms , and the inherent difficulty in providing efficient algorithms for specific computational problems....
, study the properties of computational problem
Computational problem

In theoretical computer science, a computational problem is a mathematical object representing a collection of questions that computers might want to solve....
s.






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Computer science (or computing science) is the study of the theoretical foundations of information
Information

Information as a Conveyed concept has a diversity of meanings, from everyday usage to technical settings. Generally speaking, the concept of information is closely related to notions of constraint, communication, control system, data, form, instruction, knowledge, Meaning , stimulation, pattern, perception, and knowledge representation....
 and computation
Computation

Computation is a general term for any type of information processing. This includes phenomena ranging from human thinking to calculations with a more narrow meaning....
, and of practical techniques for their implementation and application in computer
Computer

A computer is a machine that manipulates Data according to a list of Code .The first devices that resemble modern computers date to the mid-20th century , although the computer concept and various machines similar to computers existed earlier....
 systems. It is frequently described as the systematic study of algorithmic
Algorithm

In mathematics, computing, linguistics and related subjects, an algorithm is a sequence of finite instructions, often used for calculation and data processing....
 processes that describe and transform information; the fundamental question underlying computer science is, "What can be (efficiently) automated?" Computer science has many sub-fields; some, such as computer graphics
Computer graphics

Computer graphics are graphics created by computers and, more generally, the representation and manipulation of pictorial data by a computer....
, emphasize the computation of specific results, while others, such as computational complexity theory
Computational complexity theory

Computational complexity theory, as a branch of the theory of computation in computer science, investigates the problems related to the Computational resource required for the execution of algorithms , and the inherent difficulty in providing efficient algorithms for specific computational problems....
, study the properties of computational problem
Computational problem

In theoretical computer science, a computational problem is a mathematical object representing a collection of questions that computers might want to solve....
s. Still others focus on the challenges in implementing computations. For example, programming language theory
Programming language theory

Programming language theory is a branch of computer science that deals with the design, implementation, analysis, characterization, and classification of programming languages and their individual Programming language#Elements....
 studies approaches to describing computations, while computer programming
Computer programming

Computer programming is the process of writing, testing, debugging/troubleshooting, and maintaining the source code of computer programs. This source code is written in a programming language....
 applies specific programming language
Programming language

A programming language is a machine-readable artificial language designed to express computations that can be performed by a machine, particularly a computer....
s 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 vocational areas that deal with computers (such as information technology
Information technology

Information technology , as defined by the Information Technology Association of America , is "the study, design, development, implementation, support or management of computer-based information systems, particularly software applications and computer hardware." IT deals with the use of electronic computers and computer software to data conv...
), 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.

History

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
Abacus

An abacus, also called a counting frame, is a calculating tool used primarily in parts of Asia for performing arithmetic processes. Today, abacuses are often constructed as a bamboo frame with beads sliding on wires, but originally they were beans or stones moved in grooves in sand or on tablets of wood, stone, or metal....
, have existed since antiquity. Wilhelm Schickard
Wilhelm Schickard

Wilhelm Schickard was a German polymath who built one of the first calculating machines in 1623. ...
 built the first mechanical calculator in 1623. Charles Babbage
Charles Babbage

Charles Babbage, Royal Society was an England mathematician, philosopher, inventor and mechanical engineer who originated the concept of a programmable computer....
 designed a difference engine
Difference engine

The Difference Engine was an automatic, mechanical calculator designed to tabulate polynomial. Both logarithmic and trigonometric functions can be Taylor series by polynomials, so a difference engine can compute many useful sets of numbers....
 in Victorian
Victorian era

The Victorian Era of the United Kingdom of Great Britain and Ireland was the period of Victoria of the United Kingdom reign from June 1837 to January 1901....
 times helped by Ada Lovelace
Ada Lovelace

Augusta Ada King, Countess of Lovelace , born Augusta Ada Byron, was the only legitimate child of George Gordon Byron, 6th Baron Byron. She is widely known in modern times simply as Ada Lovelace....
. Around 1900, punch-card machines
Key punch

File:IBM card punch 029.JPGA key punch is a device for entering data into punched cards by precisely punching holes at locations designated by the keys struck by the operator....
 were introduced. However, all of 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. As it became clear that computers could be used for more than just mathematical calculations, the field of computer science broadened to study computation
Computation

Computation is a general term for any type of information processing. This includes phenomena ranging from human thinking to calculations with a more narrow meaning....
 in general. Computer science began to be established as a distinct academic discipline in the 1960s, with the creation of the first computer science departments and degree programs. Since practical computers became available, many applications of computing have become distinct areas of study in their own right.

Although many initially believed it 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. 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". 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.

Major achievements


Enigma
Despite its relatively short history as a formal academic discipline, computer science has made a number of fundamental contributions to science
Science

In its broadest sense, science refers to any systematic knowledge or practice. In its more usual restricted sense, science refers to a system of acquiring knowledge based on scientific method, as well as to the organized body of knowledge gained through such research....
 and society
Society

A society is a group of humans characterized by patterns of relationships between individuals that share a distinctive culture and/or institutions....
. These include:
  • Started the "digital revolution", which led to the current Information Age
    Information Age

    The Information Age is an idea that the current age will be characterised by the ability of individuals to transfer information freely, and to have instant access to knowledge that would have previously have been difficult or impossible to find....
     and the Internet
    Internet

    The Internet is a global network of interconnected computers, enabling users to share information along multiple channels. Typically, a computer that connects to the Internet can access information from a vast array of available server and other computers by moving information from them to the computer's local memory....
    .
  • A formal definition of computation
    Computation

    Computation is a general term for any type of information processing. This includes phenomena ranging from human thinking to calculations with a more narrow meaning....
     and computability, and proof that there are computationally unsolvable
    Undecidable problem

    In computability theory and computational complexity theory, an undecidable problem is a decision problem for which it is impossible to construct a single algorithm that always leads to a correct yes-or-no answer ? the problem is not Decidability ....
     and intractable problems.
  • The concept of a programming language
    Programming language

    A programming language is a machine-readable artificial language designed to express computations that can be performed by a machine, particularly a computer....
    , a tool for the precise expression of methodological information at various levels of abstraction.
  • In cryptography
    Cryptography

    Cryptography is the practice and study of hiding information. In modern times cryptography is considered a branch of both mathematics and computer science and is affiliated closely with information theory, computer security and engineering....
    , breaking the Enigma machine
    Cryptanalysis of the Enigma

    Cryptanalysis of the Enigma enabled the Allies of World War II in World War II to read substantial amounts of secret Morse code radio communications of the Axis powers enciphered using Enigma machines....
     was an important factor contributing to the Allied victory in World War II.
  • Scientific computing enabled advanced study of the mind, and mapping the human genome became possible with Human Genome Project
    Human Genome Project

    The Human Genome Project was an international scientific research project with a primary goal to determine the sequence of chemical base pairs which make up DNA and to identify and map the approximately 20,000-25,000 genes of the human genome from both a physical and functional standpoint...
    . Distributed computing
    Distributed computing

    Distributed computing deals with hardware and software systems containing more than one processing element or Computer data storage element, Concurrent computing processes, or multiple programs, running under a loosely or tightly controlled regime....
     projects such as Folding@home
    Folding@home

    Folding@home is a distributed computing project designed to perform computationally intensive simulations of protein folding and other molecular dynamics ....
     explore protein folding
    Protein folding

    Protein folding is the physical process by which a polypeptide folds into its characteristic and functional protein structure.Each protein begins as a polypeptide, translated from a sequence of mRNA as a linear chain of amino acids....
    .
  • Algorithmic trading
    Algorithmic trading

    In electronic trading, algorithmic trading or automated trading, also known as algo trading, black-box trading, or robo trading, is the use of computer programs for entering trading order with the computer algorithm deciding on certain aspects of the order such as the timing, price, or even the final quantity of the o...
     has increased the efficiency and liquidity
    Market liquidity

    Market liquidity is a business, economics or investment term that refers to an asset's ability to be easily converted through an act of buying or selling without causing a significant movement in the price and with minimum loss of value....
     of financial markets by using artificial intelligence
    Artificial intelligence

    Artificial intelligence is the intelligence of machines and the branch of computer science which aims to create it. Major AI textbooks define the field as "the study and design of intelligent agents,"...
    , machine learning
    Machine learning

    Machine learning is the subfield of artificial intelligence that is concerned with the design and development of algorithms that allow computers to improve their performance over time based on data, such as from sensor data or databases....
    , and other statistical
    Statistics

    Statistics is a Mathematics pertaining to the collection, analysis, interpretation or explanation, and presentation of data. It also provides tools for prediction and forecasting based on data....
     and numerical
    Numerical analysis

    Numerical analysis is the study of algorithms for the problems of continuous mathematics .One of the earliest mathematical writings is the Babylonian tablet YBC 7289, which gives a sexagesimal numerical approximation of , the length of the diagonal in a unit square....
     techniques on a large scale.


Fields 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. The Computer Sciences Accreditation Board (CSAB) – which is made up of representatives of the Association for Computing Machinery
Association for Computing Machinery

The Association for Computing Machinery, or ACM, was founded in 1947 as the world's first scientific and educational computing society. Its membership was approximately 83,000 as of 2007....
 (ACM), the Institute of Electrical and Electronics Engineers
Institute of Electrical and Electronics Engineers

The Institute of Electrical and Electronics Engineers or IEEE is an international non-profit, professional body for the advancement of technology related to electricity....
 Computer Society, and the Association for Information Systems
Association for Information Systems

The Association for Information Systems is an international professional organization serving as the premier global organization for academics specializing in Information Systems....
 – 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.

Theory of computation

The study of the theory of computation
Theory of computation

The theory of computation is the branch of computer science that deals with whether and how efficiently problems can be solved on a model of computation, using an algorithm....
 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
Computability theory (computer science)

In computer science, computability theory is the branch of the theory of computation that studies which problems are computationally solvable using different Model of computation....
 examines which computational problems are solvable on various theoretical models of computation. The second question is addressed by computational complexity theory
Computational complexity theory

Computational complexity theory, as a branch of the theory of computation in computer science, investigates the problems related to the Computational resource required for the execution of algorithms , and the inherent difficulty in providing efficient algorithms for specific computational problems....
, which studies the time and space costs associated with different approaches to solving a computational problem.

The famous "P=NP?" problem, one of the Millennium Prize Problems
Millennium Prize Problems

The Millennium Prize Problems are seven problems in mathematics that were stated by the Clay Mathematics Institute in 2000. Currently, six of the problems remain unsolved problems in mathematics....
, is an open problem in the theory of computation.



Theoretical computer science
The broader field of theoretical computer science
Theoretical computer science

Theoretical computer science is the collection of topics of computer science that focuses on the more abstract, logical and mathematical aspects of computing, such as the theory of computation, analysis of algorithms, and semantics of programming languages....
 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.


Algorithms and data structures



Programming methodology and languages



Computer elements and architecture



Numerical and symbolic computation



Applications

The following disciplines are often studied from a more theoretical, computer science viewpoint, as well as from a more practical, engineering perspective.



Relationship with other 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
Peter Naur

Peter Naur is a Denmark pioneer in computer science and Turing award winner. His last name is the N in the Backus-Naur form notation , used in the description of the syntax for most programming languages....
 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 ACMturingineer, turologist, flow-charts-man, applied meta-mathematician, and applied epistemologist. Three months later in the same journal, comptologist was suggested, followed next year by hypologist. The term computics has also been suggested. Informatik was a term used in Europe with more frequency.

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
Computer hardware

A personal computer is made up of computer hardware, multiple physical components onto which can be loaded into a multitude of software that perform the functions of the computer....
 is usually considered part of computer engineering
Computer engineering

Computer Engineering is a discipline that combines elements of both Electrical Engineering and Computer Science. Computer engineers are electrical engineers that have additional training in the areas of software design and hardware-software integration....
, while the study of commercial computer systems and their deployment is often called information technology
Information technology

Information technology , as defined by the Information Technology Association of America , is "the study, design, development, implementation, support or management of computer-based information systems, particularly software applications and computer hardware." IT deals with the use of electronic computers and computer software to data conv...
 or information systems
Information systems

In a general sense, the term information system refers to a system of persons, data records and activities that process the data and information in an organization, and it includes the organization's manual and automated processes....
. 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 cognitive science
Cognitive science

Cognitive science may be concisely defined as the study of the nature of intelligence. It draws on multiple empirical disciplines, including psychology, philosophy, neuroscience, linguistics, anthropology, computer science, sociology and biology....
, economics
Economics

File:Ballard Farmers' Market - vegetables.jpgEconomics is the Social sciences that studies the Production theory basics, Distribution , and Consumption of Good and Service ....
, mathematics
Mathematics

Mathematics is the study of quantity, structure, space, change, and related topics of pattern and form. Mathematicians seek out patterns whether found in numbers, space, natural science, computers, imaginary abstractions, or elsewhere....
, physics
Physics

Physics is the natural science which examines basic concepts such as energy, force, and spacetime and all that derives from these, such as mass, charge, matter and its Motion ....
 (see quantum computing), and linguistics
Linguistics

Linguistics is the science study of natural language. Linguistics encompasses a number of sub-fields. An important topical division is between the study of language structure and the study of Meaning ....
.

Computer science is considered by some to have a much closer relationship with mathematics
Mathematics

Mathematics is the study of quantity, structure, space, change, and related topics of pattern and form. Mathematicians seek out patterns whether found in numbers, space, natural science, computers, imaginary abstractions, or elsewhere....
 than many scientific disciplines, with some observers saying that computing is a mathematical science. Early computer science was strongly influenced by the work of mathematicians such as Kurt Gödel
Kurt Gödel

Kurt G?del was an Austrian-United States logician, mathematician and philosopher. One of the most significant logicians of all time, G?del made an immense impact upon scientific and philosophical thinking in the 20th century, a time when many, such as Bertrand Russell, A....
 and Alan Turing
Alan Turing

Alan Mathison Turing, Order of the British Empire, Fellow of the Royal Society was a British mathematician, logician and Cryptanalysis....
, and there continues to be a useful interchange of ideas between the two fields in areas such as mathematical logic
Mathematical logic

Mathematical logic is a subfield of mathematics and logic with close connections to computer science and philosophical logic. The field includes the mathematical study of logic and the applications of formal logic to other areas of mathematics....
, category theory
Category theory

In mathematics, category theory deals in an abstract way with mathematical structures and relationships between them: it abstracts from set s and function s to objects linked in diagrams by morphisms or arrows....
, domain theory
Domain theory

Domain theory is a branch of mathematics that studies special kinds of partially ordered sets commonly called domains. Consequently, domain theory can be considered as a branch of order theory....
, and algebra
Algebra

Algebra is a branch of mathematics concerning the study of structure , relation , and quantity. Together with geometry, mathematical analysis, combinatorics, and number theory, algebra is one of the main branches of mathematics....
.

The relationship between computer science and software engineering
Software engineering

Software engineering is the application of a systematic, disciplined, quantifiable approach to the development, operation, and maintenance of software, and the study of these approaches....
 is a contentious issue, which is further muddied by disputes
Debates within software engineering

Many debates are raging within the software engineering community. As software becomes more pervasive, most recognize the need for better software, but few agree on how to obtain it....
 over what the term "software engineering" means, and how computer science is defined. David Parnas
David Parnas

David Lorge Parnas is a Canadian early pioneer of software engineering, who developed the concept of information hiding in modular programming, which is an important element of object-oriented programming today....
, 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.

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 computational science
Computational science

Computational science is the field of study concerned with constructing mathematical models and numerical solution techniques and using computers to analyse and solve scientific, social science and engineering problems....
. Both types of departments tend to make efforts to bridge the field educationally if not across all research.

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
Theory of computation

The theory of computation is the branch of computer science that deals with whether and how efficiently problems can be solved on a model of computation, using an algorithm....
, analysis of algorithms
Analysis of algorithms

To analyze an algorithm is to determine the amount of resources necessary to execute it. Most algorithms are designed to work with inputs of arbitrary length....
, formal methods
Formal methods

In computer science and software engineering, formal methods are particular kind of mathematically-based techniques for the formal specification, development and formal verification of software and hardware systems....
, concurrency theory
Concurrency (computer science)

In computer science, concurrency is a property of systems in which several computations are executing simultaneously, and potentially interacting with each other....
, databases, computer graphics
Computer graphics

Computer graphics are graphics created by computers and, more generally, the representation and manipulation of pictorial data by a computer....
 and systems analysis
Systems analysis

Systems analysis is the interdisciplinary part of Science, dealing with analysis of sets of interacting or entities, the systems, often prior to their automation as computer systems, and the interactions within those systems....
, among others. They typically also teach computer programming
Computer programming

Computer programming is the process of writing, testing, debugging/troubleshooting, and maintaining the source code of computer programs. This source code is written in a programming language....
, 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 school
Secondary school

Secondary school is a term used to describe an educational institution where the final stage of compulsory schooling, known as secondary education, takes place....
s 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 practical aspects of computer programming are often referred to as software engineering
Software engineering

Software engineering is the application of a systematic, disciplined, quantifiable approach to the development, operation, and maintenance of software, and the study of these approaches....
. However, there is a lot of disagreement
Debates within software engineering

Many debates are raging within the software engineering community. As software becomes more pervasive, most recognize the need for better software, but few agree on how to obtain it....
 over the meaning of the term, and whether or not it is the same thing as programming.

See also


Further reading

  • Association for Computing Machinery
    Association for Computing Machinery

    The Association for Computing Machinery, or ACM, was founded in 1947 as the world's first scientific and educational computing society. Its membership was approximately 83,000 as of 2007....
    . . 1998.
  • IEEE Computer Society
    IEEE Computer Society

    IEEE Computer Society is an organizational unit of the Institute of Electrical and Electronics Engineers . It was established in 1963 when the American Institute of Electrical Engineers and the Institute of Radio Engineers merged to create the IEEE....
     and the Association for Computing Machinery
    Association for Computing Machinery

    The Association for Computing Machinery, or ACM, was founded in 1947 as the world's first scientific and educational computing society. Its membership was approximately 83,000 as of 2007....
    . . December 15, 2001.
  • Peter J. Denning
    Peter J. Denning

    Peter J. Denning is an United States computer scientist, and prolific writer. He is best known for inventing the working-set model for computer program behavior, which defeated thrashing in operating systems and became the reference standard for all memory management policies....
    . , Communications of the ACM, April 2005.
  • Donald E. Knuth. Selected Papers on Computer Science, CSLI Publications, Cambridge Univ. Press, 1996.
  • Peter J. Denning
    Peter J. Denning

    Peter J. Denning is an United States computer scientist, and prolific writer. He is best known for inventing the working-set model for computer program behavior, which defeated thrashing in operating systems and became the reference standard for all memory management policies....
    , , Technical Symposium on Computer Science Education, 2004.


External links


  • (Bertrand Meyer
    Bertrand Meyer

    Bertrand Meyer is an academic, author, and consultant in the field of computer languages. He created the Eiffel ....
    's gallery)


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