Harold Chestnut Quotes

As control engineers and scientists, we have greatly altered the way people and nations live and interact with one another. We have helped to create a world in which people live longer, enjoy better health, are better educated, and can travel and communicate over greater distances. But the systems that provide these better lives are fragile systems subject to unpredictable failures and possible destruction. We have also helped to create a world in which international relations are such that the very civilizations we have helped to build over centuries can be destroyed in a matter of hours.

From a pessimistic viewpoint, it can be stated that there is no good general way of structuring a system. However, from an optimistic point of view one can say that a number of good ways of structuring systems exist and that some are better than others for any particular system. In this and the following sections, there will be a presentation of a number of structuring approaches that have merit and have been employed successfully, including functional structuring, equipment structuring, and use of various coordinate systems.

A model may be pictorial, descriptive, qualitative, or generally approximate in nature, or it may be mathematical and quantitative in nature and reasonably precise.

A model is a qualitative or quantitative representation of a process or endeavor that shows the effects of those factors which are significant for the purposes being considered. A model may be pictorial, descriptive, qualitative, or generally approximate in nature; or it may be mathematical and quantitative in nature and reasonably precise. It is important that effective means for modeling be understood such as analog, stochastic, procedural, scheduling, flow chart, schematic, and block diagrams.

Simulation is the use of models and/or the actual conditions of either the thing being modeled or the environment in which it operates, with the models or conditions in physical, mathematical, or some other form. The purpose of simulation is to explore the various results which might be obtained from the real system by subjecting the model to representative environments which are equivalent to, or in some way representative of, the situations it is desired to understand or investigate. Simulation may involve system hardware and the actual physical environment, or it may involve mathematical models subjected to mathematical forcing or disturbance functions representative of the systems conditions to be studied.

In a world in which training and functions of individuals and groups are growing more and more specialized the number of ways to accomplish any particular result increasing. Different design, different facilities, different equipment, different methods, and different organizational means are available to meet the needs of man. It is highly desirable that we have trained persons look at these varied possibilities to compare their effectiveness, and to point the way to sound engineering decisions. Systems Engineering Methods is directed towards the development of a broad systems engineering approach to help such people improve their decision-making capability. Although the emphasis is on engineering, the systems approach can also has validity for many other areas in which emphasis may be social, economic, or political.

Those of us concerned with developing new technology should consider ourselves to have a major undertaking to try to meet the expanding needs of the increasing number of people in the world with its finite resources and environments constraints.

Finding an alternative to supplement military ways of resolving international conflicts has been taken up by many people skilled in various areas such as political science, economics, social studies, modelling and simulation, intelligence and expert systems, military strategy and weaponry as well as private business and industry.

As is used in connection with systems engineering, a model is a qualitative or quantitative representation of a process or endeavor that shows the effects of those factors which are significant for the purposes being considered. Modeling is the process of making a model. Although the model may not represent the actual phenomenon in all respects, it does describe the essential inputs, outputs, and internal characteristics, as well as provide an indication of environmental conditions similar to those of actual equipment.

The term closed loop-learning process refers to the idea that one learns by determining what s desired and comparing what is actually taking place as measured at the process and feedback for comparison. The difference between what is desired and what is taking place provides an error indication which is used to develop a signal to the process being controlled.

The Systems engineering method recognizes each system is an integrated whole even though composed of diverse, specialized structures and sub-functions. It further recognizes that any system has a number of objectives and that the balance between them may differ widely from system to system. The methods seek to optimize the overall system functions according to the weighted objectives and to achieve maximum compatibility of its parts.

Formulating consists of determining the system inputs, outputs, requirements, objectives, constraints. Structuring the system provides one or more methods of organizing the solution, the method of operation, the selection of parts, and the nature of their performance requirements. It is evident that the processes of formulating a system and structuring it are strongly related.

I should like to point out two other fields for serious attention by control people. These are (1) The need for 'optimizing the process of making automatic control', i.e. bridging the gap between theory and practice. (2) The need for working with qualified people in the social, economic, and political fields to help make the net effect of automatic control and automation a cause for hope rather than a reason for fear... The opportunities for a better world at peace make the challenge for using automation for the betterment of man one that is certainly worth working for.

The concept of a system is not a simple or unique one. There are many different kinds of systems, and different systems may be organized and operated in different ways. As individuals we all belong to some social system, we participate in an economic system, we are the product of several educational systems, and we are members of one or more family systems. In a similar fashion, the equipment of which physical systems are made may be members of many other systems, such as electrical, mechanical, sensing, actuating, energy, materials, and/or information systems. One of the challenges to the person who engineers a system is to find the many alternative ways in which the function, the operation, and/or the equipment of concern and interest may be considered, understood, and made to perform most effectively.

System costs can be considered in many different ways. For example, the cost for making the system and the cost for operating it may be used as a basic for judging the total cost. The total cost may also be arrived at in another fashion, as, for example, the sum of the fixed cost, variable cost, past investment and other charges. Furthermore, in many cases where systems engineering is required several time phases are involved for which the cost factors may be significant, such as the study phase, the breadboard phase, the prototype phase, and the production phase.