Electronic Techniques Applied to Analogue Methods of Computation

This paper describes in detail the electronic devices and principles that have been developed for the California Institute of Technology (CIT) electric analogue computer. This is a general-purpose, large-scale computer applicable to a wide range of linear and nonlinear ordinary algebraic or differential equations and linear and nonlinear partial differential equations. In addition to the basic principles of the computer, a detailed discussion is given of those elements considered to be of particular interest. These include the devices for generating the arbitrary functions of the independent variable (the excitation functions), the amplifiers for producing active linear elements such as negative impedances and for representing the nonsymmetrical terms of the matrix specifying the differential equations, the multipliers for producing arbitrary functions of the dependent variables (nonlinear elements). Performance data on these devices are presented, together with analogies and solutions of representative types of problems

Application of the California Institute of Technology Electric Analog Computer to Nonlinear Mechanics and Servomechanisms

This paper describes the non-linear elements and circuit techniques used with the California Institute of Technology electric analog computer. Their application to nonlinear mechanical vibratory systems and nonlinear servomotors is discussed in detail. These techniques have been found to be generally suitable for representing single valued nonlinear functions of a dependent variable. Nonlinear springs, spring loaded backlash, and nonlinear damping factors can be readily simulated as well as saturation effects and other single valued non-linearities in servomotors. Methods of analysis are illustrated for several typical problems including a nonlinear rotating mechanical system and an autopilot employing a solenoid-operated rate and position limited hydraulic motor. Numerous servos of this type have now been studied and correlation of computer solutions with actual servo test data have shown in every case that the mathematical equations presented here accurately describe this type of motor

Application of the California Institute of Technology Electric Analog Computer to Nonlinear Mechanics and Servomechanisms

This paper describes the non-linear elements and circuit techniques used with the California Institute of Technology electric analog computer. Their application to nonlinear mechanical vibratory systems and nonlinear servomotors is discussed in detail. These techniques have been found to be generally suitable for representing single valued nonlinear functions of a dependent variable. Nonlinear springs, spring loaded backlash, and nonlinear damping factors can be readily simulated as well as saturation effects and other single valued non-linearities in servomotors. Methods of analysis are illustrated for several typical problems including a nonlinear rotating mechanical system and an autopilot employing a solenoid-operated rate and position limited hydraulic motor. Numerous servos of this type have now been studied and correlation of computer solutions with actual servo test data have shown in every case that the mathematical equations presented here accurately describe this type of motor

Electronic Techniques Applied to Analogue Methods of Computation

This paper describes in detail the electronic devices and principles that have been developed for the California Institute of Technology (CIT) electric analogue computer. This is a general-purpose, large-scale computer applicable to a wide range of linear and nonlinear ordinary algebraic or differential equations and linear and nonlinear partial differential equations. In addition to the basic principles of the computer, a detailed discussion is given of those elements considered to be of particular interest. These include the devices for generating the arbitrary functions of the independent variable (the excitation functions), the amplifiers for producing active linear elements such as negative impedances and for representing the nonsymmetrical terms of the matrix specifying the differential equations, the multipliers for producing arbitrary functions of the dependent variables (nonlinear elements). Performance data on these devices are presented, together with analogies and solutions of representative types of problems

Declarative Specialization of Object-Oriented Programs

Designing and implementing generic software components is encouraged by languages such as object-oriented ones and commonly advocated in most application areas. Generic software components have many advantages among which the most important is reusability. However, it comes at a price: genericity often incurs a loss of efficiency. This paper presents an approach aimed at reconciling genericity and efficiency. To do so, we introduce declarations to the Java language to enable a programmer to specify how generic programs should be specialized for a particular usage pattern. Our approach has been implemented as a compiler from our extended language into standard Java. 1 Introduction The object-oriented paradigm has well-recognized advantages for application design, and more specifically for program structure. It makes it possible to decompose an application in terms of well-defined, generic components, closely corresponding to the structure of the modeled problem. This structuring leads..