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The potential for civilian mission applications of space nuclear reactor power systems is addressed in this paper. A wide range of possible civilian missions, including human and unmanned solar system exploration, are identified, along with earth-orbit applications. These missions would require versatile, high-capacity space power systems whose attributes can best be provided by nuclear technology. The long mission durations, the high power levels required to fulfill many of the challenging mission objectives, and in some instances the lack of solar energy render the use of nuclear power sources as either mission-enabling or very advantageous.

A model of cultural dynamics based on the work of Colin Renfrew is briefly described. It is shown how the general concepts of complexity and error pertain to this kind of cultural model. In particular, it is suggested that conflict in cultural contexts arises through the generation of diverse simple models of the culture, created by different members of the culture. We indicate how general system-theoretic concepts can thus be brought to bear on problems of conflict in and between cultures.

(1978). Review of: “SELF-ORGANIZATION IN NONEQUILIBRIUM SYSTEMS”, by G. Nicolis and I. Prigogine, John Wiley, New York, 1977, 491 pp. International Journal of General Systems: Vol. 4, No. 4, pp. 266-269.

One of the basic problems of the theory of control in complex systems involves determining the circumstances under which a set of control parameters can effectively manipulate a much larger number of degrees of freedom in the controlled system. Such a control capability obviously requires the presence of additional constraints relating the quantities to be controlled. We explore this general question in the context of a specific situation; namely, in terms of an algorithm recently proposed to compute the three-dimensional structures of folded polypeptides from their amino acid sequences. In this algorithm, a small number of average geometric properties (the control parameters) are utilized to determine a much larger set of inter-residue distances in the folded structure. We derive the specific condition which assures that the algorithm converges pointwise to the correct structure, which in this case turns out to involve relating rates of change of coordinates to increments in the distances consis...

We present some formal and empirical evidence to support the proposition that maximally constrained mechanical systems exhibit some of the basic properties of organisms and of machines. We show further that although such maximally constrained systems seem thereby extremely limited in their possible behaviors, they can be programmed to introduce a limitless plasticity in their behavior without breaking their constraints. We then turn to the ambiguities inherent in the word “machine”, and show that programming, in the above sense, introduces a new relation among machines; namely simulation of one machine by another. This simulation relation has none of the nice properties familiar from mathematical machine theory, basically because the causal structure in the simulator is completely different from the corresponding structure in what is being simulated. A few general implications of this state of affairs, mostly to biological problems, are discussed.

Complexity is generally viewed as an intrinsic property of certain kinds of systems, or at least, as a property of a specific description of such systems. The view towards complexity taken in the present note is different; namely, that complexity reflects the necessity for many distinct modes of description of a system. This in turn depends upon the number of ways we can effectively interact with a system, and ultimately on the number of distinct subsystems which available observational techniques make accessible to us. A number of important implications of this point of view, bearing particularly on system analysis in biology, and on reductionism as a general analytic strategy, are pointed out. The relation between the concepts of complexity, error and emergence is briefly explored.

This paper presents a survey of mathematical methods for describing complex flow behavior with a minimum number of useful parameters. The use of these techniques allows rheological measurements to be employed as an effective tool for characterizing a broad range of industrial fluids. The discussion also describes several of the more common viscometers and presents useful computer programs for these.

Political actions are undertaken with a view towards effectively improving the performance of some social system. Consideration of the nature and effect of such actions therefore fall within the framework of dynamical systems theory and control theory. In the present paper, we discuss several important general properties of such systems, with particular emphasis on how they may be controlled and regulated. The significance of these properties for understanding the temporal effects, in particular, of political actions, is discussed in some detail.

The problem of institutional planning for social systems is analogized to anticipatory modes of behavior of organisms, in which an organism's present behavior is determined by (a) sensory information about the present state of the environment, and (b) an “internal model” of the world, which makes predictions about future states on the basis of the present data and the organism's possible reactions to it. It is pointed out that, despite the obvious importance of such kinds of anticipatory systems, there is essentially no theory available for dealing with them. A class of anticipatory models, in this sense, is constructed, and its properties qualitatively explored. A number of consequences are drawn, which bear equally on planning paradigms and on organismic behavior. Prime among them are the inevitability of unforeseen “side-effects” arising from implementing plans based on necessarily incomplete models, and potential infinite regresses which arise from trying to correct for these side-effects. Some possib...

The paper explores the properties of several kinds of system description which have been employed as a framework within which to formulate and solve basic biological problems; their scope, their limitations and the relationships between them.

Some of the problems involved in finding a set of state variables for a dynamical system are formulated. Particular attention is given to the definition of topologies in which these presumptive state variables become jointly continuous, or in which a particular system dynamics is continuous. These ideas are illustrated in a number of particular examples with a bearing also on recursive function theory and on pattern recognition.

We enunciate, as a general system-theoretic principle, that any functional activity of a system typically involves only a few of the underlying structural degrees of freedom of the system. This principle has a number of important consequences, some of which are explored in this note. In particular, it is suggested that the unreliability we observe in functional organizations, and their breakdown with time, lies primarily in the fact that structural degrees of freedom, not involved directly in a particular functional activity of a system, are free for other interactions. Since the structural degrees of freedom of a system are “linked” to each other through the equations of motion of the system, such nonfunctional interactions tend to progressively interfere with the original functional activity of the system. A variety of consequences of this behavior, for biological and human-designed organizations, are explored, and a variety of mechanisms for avoiding this intrinsic dialectic in social structur...

In this present paper, the rather metaphorical ideas of ‘ positional information ’ and ‘regulation’ as used hy Wolpert (1968, 1960) in connection with morphogenesis are placed in a more general dynamical context in which those ideas are sharply defined in terms of the stability properties of classes of dynamical Systems.

It is argued, on the basis of some simple examples, that the concept of structural stability, as a scientific principle, is difficult to relate to a priori mathematical characterizations in terms of genericity or transversality. In general, the employment of mathematical objects to represent physical situations carries with it a number of tacit constraints, which impose crucial biases on the mathematics. This is illustrated by the disparity in behavior between pure real and pure imaginary eigenvalues of simple linear systems.