Johnson, T. L, Ward, S. A, Wahid, J, and Houpt, P. K
COMPUTER OPERATIONS AND HARDWARE
A laboratory design facility for digital microprocessor implementation of linear-quadratic-Gaussian feedback compensators is described. Outputs from user interactive programs for solving infinite time horizon LQ regulator and Kalman filter problems were conditioned for implementation on the laboratory microcomputer system. The software consisted of two parts: an offline high-level program for solving the LQ Ricatti equations and generating associated feedback and filter gains and a cross compiler/macro assembler which generates object code for the target microprocessor system. A PDP 11/70 with a UNIX operating system was used for all high level program and data management, and the target microprocessor system is an Intel MDS (8080-based processor). Application to the control of a two dimensional inverted pendulum is presented and issues in expanding the design/prototyping system to other target machine architectures are discussed.
NASA, Washington The Final Proc. of the Solar Power Satellite Program Rev.; p 219-222
ENERGY PRODUCTION AND CONVERSION
The choice of options for the prototype solar power satellite is addressed relative to risk and cost. Emphasis is placed on the reduction of the risk of failure. Risk is the program cost multiplied by the reduction in probability of program success due to the risky action. Four classes of risk are identified. It is suggested that prototyping would reduce the technical risk as well as reduce the effects of the other three types of risk by allowing them to be quantified earlier. Prototype demonstration requirements addressed include electromagnetic power link feasibility demonstration, component integration verification, construction technology verification, and cost performance verification. Specific prototype requirements are listed and prototyping options are given in tabular form.
'Prototyping' is frequently cited as an effective alternative technique to traditional approaches for the development of systems. This paper reviews recent literature on the subject and categorizes prototyping techniques that appear to be widely used. A large number of tools have been used for prototyping and they are discussed in relation to the technique employed and other factors in the programming environment. Issues of programming methodology raised by prototypes are also discussed.
NASA Goddard Space Flight Center Collected Software Engineering Papers, Volume 2; 20 p
COMPUTER PROGRAMMING AND SOFTWARE
The Software Engineering Laboratory was monitoring software development at NASA Goddard Space Flight Center since 1976. The data collection activities of the Laboratory and some of the difficulties of obtaining reliable data are described. In addition, the application of this data collection process to a current prototyping experiment is reviewed.