Andrew P. Sage

Closed Loop Optimization of Fixed Configuration Systems

ABSTRACT For the majority of all dynamic systems open loop optimal control generally results from optimization theory whereas a closed loop control is normally desired. By accepting a degradation in performance a closed loop control termed ‘ specific optimal control ’ can be obtained. A series of experiments were performed investigating this type of sub-optimal control. It was found that although the proper choice of the control parameter leads to easily implemented closed loop controls, there are major drawbacks to its use. The coefficients in the control law ore highly dependent upon the final time T, the system parameters, and the initial state of the system. Furthermore, the performance of the system was found to be a function of the algebraic form chosen for the control law. To determine the most optimum control law entails performing a series of computer experiments. This last difficulty may be circumvented in part by embedding the specific optimal control problem in an identification problem. Resul...

Modeling and Simulation in Systems Engineering Whither Simulation Based Acquisition

Simulation and modeling are major assets in the engineering of systems of all types. This two-part series addresses the much expanded role for M&S that is due to the prospect that evolutionary and adaptive engineering efforts are the wave of the future. The Department of Defenses Simulation BasedAcquisition initiative is a case in point, but some critical issues need to be addressed to bring it to fruition. In this first part, we set the background in systems engineering, information technology and the new role of complex adaptive system models that are changing our view of organizations as machines to organizations as organisms.

Optimum design and error analysis of digital integrators for discrete system simulation

In digital differential analyzers and digital computers, simulation is carried out by some form of numerical integration or of replacing a difference differential equation by a difference equation. This paper is concerned with the development of optimum numerical integration and digital simulation techniques and a discussion of the accuracy of these methods when compared with ideal integration.

Least-Squares Curve Fitting and Discrete Optimum Fitting

This tutorial paper presents an introduction to leastsquares curve fitting and its connection to optimum filtering, using methods familiar and appealing to communication and control system engineers and educators in these disciplines. A development of the remarkable computational contribution of Kalman and Bucy to the solution of the Wiener filtering problem is presented, using leastsquares techniques and the Bayesian rule. Since the approach is discrete, the paper stresses the role of the modem digital computer in solving this class of important electrical engineering problems.

The Role of Systems Engineering in Electrical Engineering Education

Systems Engineering, including its subspecialties, has much to offer and is a needed component in electrical engineering education. Inclusion of efforts in systems engineering philosophy and methodology within the electrical engineering curriculum can do much towards the enhancement of student achievement of technical and management proficiency and, perhaps more importantly, towards achievement of appreciation of the vital role of the human element in resolution of large scale problems through technology. A framework for an introductory systems engineering course is described.

Whither Simulation Based Acquisition ?: Part II: Modeling and Simulation in Systems Engineering

Crack stops for substantially preventing cracks and chips produced along the dicing channel from spreading into the active areas of the ICs are described. The crack stops are formed by creating discontinuities in the thickness of the dielectric layer in the dicing channel near the chip edges. The discontinuities can result in increasing and/or decreasing the thickness of the dielectric layer.

Error Analysis, Sensitivity, and Prior Statistics

Methods of statistical interference including estimation and modem filter theory are finding ever-increasing application in electrical engineering problems. Two problems which occur when methods of modem estimation theory are applied to a physical problem are the choice of prior statistics and the choice of a mathematical model for the system. This paper provides a fundamental and tutorial discussion of the role of error analysis, sensitivity, and prior statistics in classical point estimation. Thus, it provides the framework for study and research into varied aspects of this problem in more difficult and realistic situations.

An Efficient Method for Digital Simulation and Modeling of Linear Communication and Control Systems

The need for digital simulation or modeling of linear modulated communication and control systems frequently arises. This paper presents a method for accomplishing this task which has outstanding computational efficiency. It applies to those situations in which the input to the modulator or detector can be presented as a sum of sinusoids of arbitrary amplitudes, phases, and frequencies. Post modulator or post detector filtering is assumed to be accomplished by a linear stationary differential system. The method is considerably more efficient than conventional methods because the action of the modulator or detector is accounted for analytically and because an alternate expression for the transition matrix is employed which eliminates derivatives of the input signal from the integrand of the convolution of the transition matrix. The advantages accruing to these measures are demonstrated by two examples, one of which is frequently encountered in discrete phaselock loops and in identification of system parameters by sinusoidal response methods.

Electronic simulation of daily rhythm in nocturnal animals

The term biological clock is used to designate the phenomenon, displayed by organisms, of pacing activity in a cyclic manner related to environment. Many nocturnal animals, for example, are capable of entraining the onset of their activity with the light-to- dark transition in a periodic light-dark regime in which the period or ratio of light to darkness varies widely. This paper presents the development of an electronic model for simulation of the adaptation of the endogenous circadian rhythm of nocturnal ani mals due to light stimuli.