B. Jack Copeland (ed.)
- Published in print:
- 2005
- Published Online:
- January 2008
- ISBN:
- 9780198565932
- eISBN:
- 9780191714016
- Item type:
- book
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780198565932.001.0001
- Subject:
- Mathematics, History of Mathematics
The mathematical genius Alan Turing (1912-1954) was one of the greatest scientists and thinkers of the 20th century. Now well known for his crucial wartime role in breaking the ENIGMA code, he was ...
More
The mathematical genius Alan Turing (1912-1954) was one of the greatest scientists and thinkers of the 20th century. Now well known for his crucial wartime role in breaking the ENIGMA code, he was the first to conceive of the fundamental principle of the modern computer — the idea of controlling a computing machine's operations by means of coded instructions, stored in the machine's ‘memory’. In 1945, Turing drew up his revolutionary design for an electronic computing machine — his Automatic Computing Engine (‘ACE’). A pilot model of the ACE ran its first programme in 1950 and the production version, the ‘DEUCE’, went on to become a cornerstone of the fledgling British computer industry. The first ‘personal’ computer was based on Turing's ACE. This book describes Turing's struggle to build the modern computer. It contains first-hand accounts by Turing and by the pioneers of computing who worked with him. The book describes the hardware and software of the ACE and contains chapters describing Turing's path-breaking research in the fields of Artificial Intelligence (AI) and Artificial Life (A-Life).Less
The mathematical genius Alan Turing (1912-1954) was one of the greatest scientists and thinkers of the 20th century. Now well known for his crucial wartime role in breaking the ENIGMA code, he was the first to conceive of the fundamental principle of the modern computer — the idea of controlling a computing machine's operations by means of coded instructions, stored in the machine's ‘memory’. In 1945, Turing drew up his revolutionary design for an electronic computing machine — his Automatic Computing Engine (‘ACE’). A pilot model of the ACE ran its first programme in 1950 and the production version, the ‘DEUCE’, went on to become a cornerstone of the fledgling British computer industry. The first ‘personal’ computer was based on Turing's ACE. This book describes Turing's struggle to build the modern computer. It contains first-hand accounts by Turing and by the pioneers of computing who worked with him. The book describes the hardware and software of the ACE and contains chapters describing Turing's path-breaking research in the fields of Artificial Intelligence (AI) and Artificial Life (A-Life).
L. Jean Camp
- Published in print:
- 2006
- Published Online:
- January 2012
- ISBN:
- 9780197263839
- eISBN:
- 9780191734915
- Item type:
- chapter
- Publisher:
- British Academy
- DOI:
- 10.5871/bacad/9780197263839.003.0011
- Subject:
- Political Science, Political Theory
As governmental processes and judgments become increasingly digital, the transparency of digital systems that implement the processes of government becomes increasingly important. Open code is a ...
More
As governmental processes and judgments become increasingly digital, the transparency of digital systems that implement the processes of government becomes increasingly important. Open code is a necessary but not sufficient prerequisite for maintaining transparency as democracy becomes digitized, and complete openness of process is not appropriate for every domain. This chapter explores some of the complexities in the relationship between openness of code and democratic government. Computer code controls and enables the actions of users, and for users to have true autonomy they must be able to examine, alter, and redistribute the code. A key issue for transparency is the degree to which this observation applies to the activities of government that are embedded in computer code. Free software creates a fundamentally different market structure than closed code. The philosophy of free software argues that the inability to view code that implements governance suggests totalitarian and Kafkaesque control, a constraining complex network of rules and regulations.Less
As governmental processes and judgments become increasingly digital, the transparency of digital systems that implement the processes of government becomes increasingly important. Open code is a necessary but not sufficient prerequisite for maintaining transparency as democracy becomes digitized, and complete openness of process is not appropriate for every domain. This chapter explores some of the complexities in the relationship between openness of code and democratic government. Computer code controls and enables the actions of users, and for users to have true autonomy they must be able to examine, alter, and redistribute the code. A key issue for transparency is the degree to which this observation applies to the activities of government that are embedded in computer code. Free software creates a fundamentally different market structure than closed code. The philosophy of free software argues that the inability to view code that implements governance suggests totalitarian and Kafkaesque control, a constraining complex network of rules and regulations.
Gary A. Glatzmaier
- Published in print:
- 2013
- Published Online:
- October 2017
- ISBN:
- 9780691141725
- eISBN:
- 9781400848904
- Item type:
- book
- Publisher:
- Princeton University Press
- DOI:
- 10.23943/princeton/9780691141725.001.0001
- Subject:
- Physics, Particle Physics / Astrophysics / Cosmology
This book provides readers with the skills they need to write computer codes that simulate convection, internal gravity waves, and magnetic field generation in the interiors and atmospheres of ...
More
This book provides readers with the skills they need to write computer codes that simulate convection, internal gravity waves, and magnetic field generation in the interiors and atmospheres of rotating planets and stars. Using a teaching method perfected in the classroom, the book begins by offering a step-by-step guide on how to design codes for simulating nonlinear time-dependent thermal convection in a 2D box using Fourier expansions in the horizontal direction and finite differences in the vertical direction. It then describes how to implement more efficient a nd accurate numerical methods and more realistic geometries in two and three dimensions. The third part of the book demonstrates how to incorporate more sophisticated physics, including the effects of magnetic field, density stratification, and rotation. The book features numerous exercises throughout, and is an ideal textbook for students and an essential resource for researchers. It explains how to create codes that simulate the internal dynamics of planets and stars, and builds on basic concepts and simple methods. The book shows how to improve the efficiency and accuracy of the numerical methods. It considers more relevant geometries and boundary conditions.Less
This book provides readers with the skills they need to write computer codes that simulate convection, internal gravity waves, and magnetic field generation in the interiors and atmospheres of rotating planets and stars. Using a teaching method perfected in the classroom, the book begins by offering a step-by-step guide on how to design codes for simulating nonlinear time-dependent thermal convection in a 2D box using Fourier expansions in the horizontal direction and finite differences in the vertical direction. It then describes how to implement more efficient a nd accurate numerical methods and more realistic geometries in two and three dimensions. The third part of the book demonstrates how to incorporate more sophisticated physics, including the effects of magnetic field, density stratification, and rotation. The book features numerous exercises throughout, and is an ideal textbook for students and an essential resource for researchers. It explains how to create codes that simulate the internal dynamics of planets and stars, and builds on basic concepts and simple methods. The book shows how to improve the efficiency and accuracy of the numerical methods. It considers more relevant geometries and boundary conditions.
Gary A. Glatzmaier
- Published in print:
- 2013
- Published Online:
- October 2017
- ISBN:
- 9780691141725
- eISBN:
- 9781400848904
- Item type:
- chapter
- Publisher:
- Princeton University Press
- DOI:
- 10.23943/princeton/9780691141725.003.0008
- Subject:
- Physics, Particle Physics / Astrophysics / Cosmology
This chapter focuses on time integration schemes, including fourth-order accurate Runge–Kutta and predictor-corrector schemes as well as schemes that allow larger time steps (and therefore fewer ...
More
This chapter focuses on time integration schemes, including fourth-order accurate Runge–Kutta and predictor-corrector schemes as well as schemes that allow larger time steps (and therefore fewer steps for a given amount of simulated time) by treating the linear diffusion terms implicitly. The nonlinear terms, however, couple all the modes and so would be extremely expensive to treat implicitly; therefore they are usually treated explicitly. Such “semi-implicit” schemes considerably improve the efficiency of the computer code. The chapter also describes the Crank–Nicolson scheme and concludes by showing how the current numerical model can easily be modified to study mantle convection (also called “geodynamics”) using the vorticity equation in the limit of an infinite Prandtl number.Less
This chapter focuses on time integration schemes, including fourth-order accurate Runge–Kutta and predictor-corrector schemes as well as schemes that allow larger time steps (and therefore fewer steps for a given amount of simulated time) by treating the linear diffusion terms implicitly. The nonlinear terms, however, couple all the modes and so would be extremely expensive to treat implicitly; therefore they are usually treated explicitly. Such “semi-implicit” schemes considerably improve the efficiency of the computer code. The chapter also describes the Crank–Nicolson scheme and concludes by showing how the current numerical model can easily be modified to study mantle convection (also called “geodynamics”) using the vorticity equation in the limit of an infinite Prandtl number.
Gary A. Glatzmaier
- Published in print:
- 2013
- Published Online:
- October 2017
- ISBN:
- 9780691141725
- eISBN:
- 9781400848904
- Item type:
- chapter
- Publisher:
- Princeton University Press
- DOI:
- 10.23943/princeton/9780691141725.003.0006
- Subject:
- Physics, Particle Physics / Astrophysics / Cosmology
This chapter focuses on internal gravity waves in a stable thermal stratification. When the amplitude of the fluid velocity is small relative to the amplitude of the phase velocity, a linear ...
More
This chapter focuses on internal gravity waves in a stable thermal stratification. When the amplitude of the fluid velocity is small relative to the amplitude of the phase velocity, a linear analysis, which neglects advection, provides insight to the relation between the wavelength and frequency of internal gravity waves. Furthermore, when thermal and viscous diffusion play relatively minor roles the system can be further simplified by neglecting diffusion. The chapter first describes the linear dispersion relation before discussing the computer code modifications and simulations. In particular, it explains what modifications would be needed to convert one's thermal convection code to a code that simulates internal gravity waves, including the nonlinear and diffusive terms. Finally, it considers the computer analysis of wave energy.Less
This chapter focuses on internal gravity waves in a stable thermal stratification. When the amplitude of the fluid velocity is small relative to the amplitude of the phase velocity, a linear analysis, which neglects advection, provides insight to the relation between the wavelength and frequency of internal gravity waves. Furthermore, when thermal and viscous diffusion play relatively minor roles the system can be further simplified by neglecting diffusion. The chapter first describes the linear dispersion relation before discussing the computer code modifications and simulations. In particular, it explains what modifications would be needed to convert one's thermal convection code to a code that simulates internal gravity waves, including the nonlinear and diffusive terms. Finally, it considers the computer analysis of wave energy.
Brad J. Sagarin and Kevin D. Mitnick
- Published in print:
- 2012
- Published Online:
- March 2015
- ISBN:
- 9780199743056
- eISBN:
- 9780190255916
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:osobl/9780199743056.003.0003
- Subject:
- Psychology, Social Psychology
This chapter examines how “social engineering” can be used in computer hacking to gain access to highly secret computer codes and other confidential information, and how to defend yourself against ...
More
This chapter examines how “social engineering” can be used in computer hacking to gain access to highly secret computer codes and other confidential information, and how to defend yourself against such influence-based attacks. Drawing on Robert Cialdini's principles of influence, the chapter explores the concept of resistance to unwanted persuasion by describing Motorola's experience with a social engineering attack from the perspective of the perpetrator. It also considers the points of vulnerability exploited by the attack and the methods by which individuals and organizations can protect themselves against such attacks and thus avoid the path of least resistance.Less
This chapter examines how “social engineering” can be used in computer hacking to gain access to highly secret computer codes and other confidential information, and how to defend yourself against such influence-based attacks. Drawing on Robert Cialdini's principles of influence, the chapter explores the concept of resistance to unwanted persuasion by describing Motorola's experience with a social engineering attack from the perspective of the perpetrator. It also considers the points of vulnerability exploited by the attack and the methods by which individuals and organizations can protect themselves against such attacks and thus avoid the path of least resistance.
Vilém Flusser, Mark Poster, and Nancy Ann Roth
- Published in print:
- 2011
- Published Online:
- August 2015
- ISBN:
- 9780816670222
- eISBN:
- 9781452947228
- Item type:
- chapter
- Publisher:
- University of Minnesota Press
- DOI:
- 10.5749/minnesota/9780816670222.003.0008
- Subject:
- Society and Culture, Media Studies
This chapter discusses programming as a new way of writing directed toward apparatuses instead of human beings and one that is meant to issue instructions. Children all learn the alphabet, and print ...
More
This chapter discusses programming as a new way of writing directed toward apparatuses instead of human beings and one that is meant to issue instructions. Children all learn the alphabet, and print has resulted in a comprehensive, democratizing literacy. However, new computer codes makes everybody illiterate again. For most of us, computer programs are suffused with the kind of mystery that surrounded alphabetic writing prior to the invention of print. If a program is to be understood as writing directed not toward human beings but toward apparatuses, then people have been programming since writing was invented—before there were any apparatuses. Because programs instruct apparatuses, the burden of instruction shifts from human beings to inanimate objects, and human beings become free to behave as they like. From this standpoint, the tendency inherent in instructions and culminating in programs is aimed at freedom. Whether programming will render all writing obsolete remains an open question.Less
This chapter discusses programming as a new way of writing directed toward apparatuses instead of human beings and one that is meant to issue instructions. Children all learn the alphabet, and print has resulted in a comprehensive, democratizing literacy. However, new computer codes makes everybody illiterate again. For most of us, computer programs are suffused with the kind of mystery that surrounded alphabetic writing prior to the invention of print. If a program is to be understood as writing directed not toward human beings but toward apparatuses, then people have been programming since writing was invented—before there were any apparatuses. Because programs instruct apparatuses, the burden of instruction shifts from human beings to inanimate objects, and human beings become free to behave as they like. From this standpoint, the tendency inherent in instructions and culminating in programs is aimed at freedom. Whether programming will render all writing obsolete remains an open question.
John A. Tossell and David J. Vaughan
- Published in print:
- 1992
- Published Online:
- November 2020
- ISBN:
- 9780195044034
- eISBN:
- 9780197560013
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/oso/9780195044034.003.0005
- Subject:
- Earth Sciences and Geography, Geochemistry
In this chapter, the most important quantum-mechanical methods that can be applied to geological materials are described briefly. The approach used follows that of ...
More
In this chapter, the most important quantum-mechanical methods that can be applied to geological materials are described briefly. The approach used follows that of modern quantum-chemistry textbooks rather than being a historical account of the development of quantum theory and the derivation of the Schrödinger equation from the classical wave equation. The latter approach may serve as a better introduction to the field for those readers with a more limited theoretical background and has recently been well presented in a chapter by McMillan and Hess (1988), which such readers are advised to study initially. Computational aspects of quantum chemistry are also well treated by Hinchliffe (1988). In the section that follows this introduction, the fundamentals of the quantum mechanics of molecules are presented first; that is, the “localized” side of Fig. 1.1 is examined, basing the discussion on that of Levine (1983), a standard quantum-chemistry text. Details of the calculation of molecular wave functions using the standard Hartree-Fock methods are then discussed, drawing upon Schaefer (1972), Szabo and Ostlund (1989), and Hehre et al. (1986), particularly in the discussion of the agreement between calculated versus experimental properties as a function of the size of the expansion basis set. Improvements on the Hartree-Fock wave function using configuration-interaction (CI) or many-body perturbation theory (MBPT), evaluation of properties from Hartree-Fock wave functions, and approximate Hartree-Fock methods are then discussed. The focus then shifts to the “delocalized” side of Fig. 1.1, first discussing Hartree-Fock band-structure studies, that is, calculations in which the full translational symmetry of a solid is exploited rather than the point-group symmetry of a molecule. A good general reference for such studies is Ashcroft and Mermin (1976). Density-functional theory is then discussed, based on a review by von Barth (1986), and including both the multiple-scattering self-consistent-field Xα method (MS-SCF-Xα) and more accurate basis-function-density-functional approaches. We then describe the success of these methods in calculations on molecules and molecular clusters. Advances in density-functional band theory are then considered, with a presentation based on Srivastava and Weaire (1987). A discussion of the purely theoretical modified electron-gas ionic models is followed by discussion of empirical simulation, and we conclude by mentioning a recent approach incorporating density-functional theory and molecular dynamics (Car and Parrinello, 1985).
Less
In this chapter, the most important quantum-mechanical methods that can be applied to geological materials are described briefly. The approach used follows that of modern quantum-chemistry textbooks rather than being a historical account of the development of quantum theory and the derivation of the Schrödinger equation from the classical wave equation. The latter approach may serve as a better introduction to the field for those readers with a more limited theoretical background and has recently been well presented in a chapter by McMillan and Hess (1988), which such readers are advised to study initially. Computational aspects of quantum chemistry are also well treated by Hinchliffe (1988). In the section that follows this introduction, the fundamentals of the quantum mechanics of molecules are presented first; that is, the “localized” side of Fig. 1.1 is examined, basing the discussion on that of Levine (1983), a standard quantum-chemistry text. Details of the calculation of molecular wave functions using the standard Hartree-Fock methods are then discussed, drawing upon Schaefer (1972), Szabo and Ostlund (1989), and Hehre et al. (1986), particularly in the discussion of the agreement between calculated versus experimental properties as a function of the size of the expansion basis set. Improvements on the Hartree-Fock wave function using configuration-interaction (CI) or many-body perturbation theory (MBPT), evaluation of properties from Hartree-Fock wave functions, and approximate Hartree-Fock methods are then discussed. The focus then shifts to the “delocalized” side of Fig. 1.1, first discussing Hartree-Fock band-structure studies, that is, calculations in which the full translational symmetry of a solid is exploited rather than the point-group symmetry of a molecule. A good general reference for such studies is Ashcroft and Mermin (1976). Density-functional theory is then discussed, based on a review by von Barth (1986), and including both the multiple-scattering self-consistent-field Xα method (MS-SCF-Xα) and more accurate basis-function-density-functional approaches. We then describe the success of these methods in calculations on molecules and molecular clusters. Advances in density-functional band theory are then considered, with a presentation based on Srivastava and Weaire (1987). A discussion of the purely theoretical modified electron-gas ionic models is followed by discussion of empirical simulation, and we conclude by mentioning a recent approach incorporating density-functional theory and molecular dynamics (Car and Parrinello, 1985).
