systems-engineers

"I had professor Machol at Kellogg in 1985 for Operations. Professor Machol was intimidating. Rumor around the class was that he had been in charge of logistics for the U.S. Navy in the Pacific theatre during WWII. He was teaching EOQ modeling in one early class, leading me to pose a question, ‘Professor Machol, would it not make sense to do … for the sake of consistency’. His reply is oh so memorable almost 40 years ago.. “Mr. Clark, consistency is the bugaboo of small minds” (ouch!). No doubt relative to this giant, my mind was and remains small indeed!"

"Feedback: It is the fundamental principle that underlies all self-regulating systems, not only machines but also the processes of life and the tides of human affairs."

"Already well known to engineers all over the world as a pioneer in the development of automatic control, it may well turn out that Gordon Brown will make a still deeper mark on the engineering development of this century."

"He is transported to that curious world of decibels and negative frequencies where filter experts live."

"Methods by which engineers stabilise their mechanisms suggest analogous possibilities for stabilising economic systems."

"When beliefs need some modification, We make it with much trepidation, For our world is then new, And things seem all askew, 'til we're used to the new formulation."

"The topic that I have attempted to explore is the usefulness of these notions of the engineer, about feeds-back, harmonic components and the like, in application to the analogous problems of economic fluctuation and economic regulation."

"The analysis of engineering systems and the understanding of economic structure have advanced since then, and the time is now more ripe to bring these topics into a potentially fruitful marriage."

"The ‘theory of control systems’ in engineering is now a well-developed subject, making use of some remarkably powerful concepts and methods of analysis, especially in relation to problems of stabilization and the prevention of unwanted oscillations."

"Consideration of a further possibility, namely that of constructing physical systems that are analogues of the economic system, and of observing and recording their behaviour."

"An economic system is not a linear system, and... this fact stands in the way of the determination of the parameters of the system by methods that presume linearity, and... it introduces great difficulties in the extrapolation from past behaviour for purposes of prediction."

"The nature of the instability of an unregulated free-enterprise system is only now beginning to be clearly understood. Perhaps the degree of understanding already attained ensures that the grosser shortcomings have gone for ever, and to that extent the conflict between Capitalism and Communism is about issues that belong to the past. It may now be too late. The gods must smile to note how different the state of the world might have been if the progress of economic thought of the last twenty years had been advanced by even ten years. The possibility of a stable economic life with full utilization of our resources is still not sufficiently assured, and it is extremely important that it should be so assured, and that the whole world should accept this as a fact. The work that is being done in econometrics is massive, and undaunted by mathematical difficulties, but it appears, at any rate as viewed from outside, to be unclear as to its aim."

"The striking parallel between the economic models that are currently under discussion and some engineering systems suggests the hope that in some way the rapid progress in the development of the theory and practice of automatic control in the world of engineering may contribute to the solution of the economic problems."

"It is possible that the major collaboration between economists and engineers is still to come, in the greater use of physical analogues and computers of the analogue type to avoid the difficulties of calculation. Apart from their major use as possible tools for economic regulation, physical analogues have a subsidiary use, for there are students of economics, as there are many students of engineering, who can better understand the significance of the somewhat formidable mathematics that tends to be used in this field, if they can first acquaint themselves with the types of behaviour in question as exhibited by physical objects that can be seen, felt, handled and experimented with. It may also be suggested that economists may find that what they have to say about economic policy will be very readily assimilated by one group of attentive pupils, namely the scientists, engineers and technicians of industry, if explanatory notions can be drawn from the theory of automatic control, which is now part of a normal engineering education. The aim of this essay has been to give explanations of system behaviour, and some approaches to its analysis, using geometrical construction and physical analogy where possible to clarify the implications of the more usual formal algebraic approach."

"The separate excitation of the dynamo corresponds with the independently determined investment in the economic model, and the total excitation with income. Perhaps in this electrical age, the conventional metaphor of ‘priming the pump’ might be dropped in favour of ‘exciting the dynamo’."

"Actual economic systems are constantly subjected to change and disturbances, which would result in irregularity."

"The writer, who as an engineer has spent most of his life in factories, is inclined to look at the basis for investment from a technological point of view... Consider … the class of industrial investments only... The situation is one of entrepreneurs and boards of directors considering, from time to time, various ’possibilities of investment’, such as extra lathes or looms, an extension to a factory, a venture in some completely new product, and so on. It is helpful to think of these ’opportunities for investment’ as existing, in a given situation, in great number and variety, whether they are at that moment under active consideration or not. When any such possibility is considered it is assessed in respect of ’expected profitability’. One may conveniently think of all possibilities of investment as ’quanta’ that can be placed in a schedule of small ranges of expected profitability according to these assessments. The placement of a given ’opportunity for investment’ on this schedule has some ’margin of uncertainty’ (a curious analogy with the case of the quanta of physics)."

"Simulators set up the required system of interdependences, usually between electrical potentials or voltages as variables, by means of valve-amplifiers and electrical networks. Since the voltage across a capacitance is proportional to the integral of a current, that across an inductance to the first derivative of a current, and that across a resistor to the current itself, it is possible to arrange a network of electrical elements, with amplifiers and feeds-back where necessary, so that a given linear differential equation is caused to relate an ’output’ voltage to an ’input’ voltage. Thus a given linear system of interdependences can be simulated, either directly or in any convenient transformation. If non-linear relationships are required there is no universally applicable simple device, but there do exist a great variety of non-linear elements with non-linear characteristics that are known and to some extent; adjustable. These include non-linear resistors... and the characteristic curves of thermionic valves, of rectifiers and discharge vessels and of magnetic materials. Limits may be set by the use of neon tubes that become conducting when a certain voltage is exceeded, or by relays, and so on"

"Once a full-employment policy has been adopted... the economic ’system’ just on that account is significantly different. Its equilibrium position has been shifted to a rising curve of trend close to and following the employment ceiling. The conditions of stability about this new level are radically different because the region of operation is now within the less flexible and sharply non-linear range of employment saturation"

"There are certain formal similarities between the problems of devising policies for economic stabilisation and those of designing automatic control systems. Methods have recently been developed by engineers for analysing the dynamic properties of quite complex models... [which] can also be used for the analysis of dynamic process models in economics... Professor Tustin’s book contains material of fundamental importance for all who are engaged in either theoretical or empirical studies of dynamic processes in economics. It throws new light on the possibilities and the difficulties of quantitative research in this field."

"Two kinds of self-controlling machines exist: the regulators whose effect has a fixed value and the Servo-mechanisms whose effect has a value depending on the value of a variable which is the “control.” The idea is simple and reveals itself to be accurate. We have found it confirmed by the technical authority, Prof. Arnold Tustin, of the University of Birmingham, who during the war elaborated a system for the movement of gun turrets and naval guns. According to him, if a machine were entrusted with driving a car, it would be a regulator on a straight road and a servo on a winding one."

"During the early phase of World War II, Britain was challenged to refine the understanding of human control of tanks and aircraft. The first engineering-oriented manual control models were probably those of Prof. Arnold Tustin in the United Kingdom applied to tank-control, followed closely by models by J.P. North of Boulton- Paul Aircraft Co."

"Arnold Tustin (1899–1994) introduced the that bears his name to the control community to relate discrete-time and continuous-time systems."

"Arnold Tustin is best known for his contributions to control theory and its application to electrical machines. However, his interests were much wider than electrical engineering, for he was a polymath who brought a systems approach to each of the many areas that he investigated. In the modern jargon he thought ‘outside the box’ and in doing so championed the use of control systems theory beyond its traditional limits. His impact was such that, in addition to his engineering contributions, he is well known for his systems treatment of economics and to a lesser extent... biology."

"Systems engineering is most effectively conceived of as a process that starts with the detection of a problem and continues through problem definition, planning and designing of a system, manufacturing or other implementing section, its use, and finally on to its obsolescence. Further, Systems engineering is not a matter of tools alone; It is a careful coordination of process, tools and people."

"Arthur D. Hall (1962) identified five traits of the ideal systems engineer and these certainly still stand today; these traits are: (1) an affinity for the systems … (2) faculty of judgment, (3) creativity, (4) facility in human relations, and (5) a for expression. The specific role of the systems engineer has traditionally been rather inwardly focused, with considerations to environment and external systems. In this broader field of Engineering Systems, the systems engineering practitioners may need to re-evaluate their roles and responsibilities in the overall systems effort."

"The motives for conceiving modern systems engineering are to be found, at least in part, in past disasters. Arthur D. Hall III [1989] cites: the chemical plant leakage in Bhopal (1986); the explosion of the NASA Challenger space shuttle (1986) and the Apollo fire (1967); the sinking of the Titanic (1912); the nuclear explosion in Chernobyl (1986) and the disaster at Three Mile Island power plant (1979). He cites, too, the capture of markets by Japan from the U.S., the decline in US productivity and the failure of the US secondary school system. He identifies the millions of people dying of starvation every year while other nations stockpile surplus food, medical disasters such as heart disease, while governments subsidize grains used to produce high cholesterol meat, milk and eggs; and many more. One implication is clear: systems engineering faces challenges well beyond the sphere of engineering."

"A.D. Hall's (1962) classic account of the methodology was based on his experience with the Bell Telephone Laboratories. Hall sees systems as existing in hierarchies. In systems engineering, plans to achieve a general objective must similarly be arranged in a hierarchy, with the systems engineer ensuring the internal consistency and integration of the plans, The methodology itself ensures the optimization of the system of concern with respect to its objectives. This requires a number of steps, the most important being problem definition, choosing objectives, systems synthesis, systems analysis, systems selection, system development, and current engineering. With Hall, the system of concern is usually a physical entity."

"The basic functional elements of any automatic control system: sensing, converting, storing, communicating, computing, programming, regulating, actuating, and display (Chestnut, 1967). Many kinds of systems in being, speculated about, or even intuited, ranging from computers, most factory processes, communication systems, road networks, automatic farms, etc., have structures which can be invoked as zero-order matches to proposed sets of throughputs, especially for single- thread designs. This method of structuring is related closely to analogical design, of which a special form is called synectics."

"History becomes one model needed to give a rounded view of our subject within the philosophy of hierarchical holographic modeling, defined as using a family of models at several levels to seek understanding of diverse aspects of a subject and thus comprehend the whole."

"Has mankind evolved to a point that there exists, or that with creative additions and re-combinations of modest proportions, there can be shown to be available, a common systems methodology, in terms of which we can conceive of, plan, design, construct, and use systems (procedures, machines, teams of people) of any arbitrary type in the service of mankind, and with low rates of failure?"

"The operational sciences hoped to nourish business management, which however largely ignored them, and the latter continues to be undernourished by the business schools which are fairly broad but shallow everywhere. By over focus on short-range financial values, business management in the United States has lost a dozen major markets to the Japanese, added pollution in all its forms, and enriched itself out of all proportion to its value as just one factor of production. Action science, developed by the social sciences over many years in relative isolation from the applied physical sciences, and which might otherwise have humanized them and made engineering more productive, was doomed to fail by being on one end of the two-culture problem wherein science and the humanities do not even speak the same language. I could go on listing a few dozen paradigms: art, law, computer software design, medicine, politics, and architecture, each addressed to a certain context, level, or phase, each good in itself, but each limited to the fields of its origin and its purposes. The methodological problem is the same as if, in designing any large system, each subsystem designer were left to design each subsystem to the best requirements he knew. The overall requirement might not be met; overall harmony could not be achieved, and conflict could ensue to cause failure at the system level. What is envisioned is a new synthesis, a unified, efficient, systems methodology (SM): a multiphase, multi-level, multi-paradigmatic creative problem-solving process for use by individuals, by small groups, by large multi-disciplinary teams, or by teams of teams. It satisfies human needs in seeking value truths by matching the properties of wanted systems, and their parts, to perform harmoniously with their full environments, over their entire life cycles"

"God made Homo sapiens a problem-solving creature. The trouble is that He gave us too many resources: too many languages, too many phases of life, too many levels of complexity, too many ways to solve problems, too many contexts in which to solve them, and too many values to balance. First came the law, accounting, and history which looks backward in time for their values and decision-making criteria, but their paradigm (casuistry) cannot look forward to predict future consequences. Casuistry is overly rigid and does not account for statistical phenomena. To look forward man used two thousand years to evolve scientific method - which can predict the future when it discovers the laws of nature. In parallel, man evolved engineering, and later, systems engineering, which also anticipates future conditions. It took man to the moon, but it often did, and does, a poor job of understanding social systems, and also often ignores the secondary effects of its artifacts on the environment. Environmental impact analysis was promoted by governments to patch over the weakness of engineering - with modest success - and it does not ignore history; but by not integrating with system design, it is also an incomplete philosophy. System design and architecture, or simply design, like science and engineering is forward-looking, and provides man with comforts and conveniences - if someone will tell them what problems to solve, and which requirements to meet. It rarely collects wisdom from the backward-looking methodologies, often overlooks ordinary operating problems in designing its artifacts, whether autos or buildings, and often ignores the principles of good teamwork."

"A system is a set of objects with relationships between the … in may be described generally as a complex of elements or components directly or indirectly related in a causal network, … Also, we are mainly interested in systems within which some process is continually going on, including an interchange with an environment across the boundary. It is generally agreed that when we deal with the more open system with a highly flexible structure, the distinction between the boundaries and the environment becomes a more and more arbitrary matter, dependent upon the purpose of the observer."

"Every part of the system is so related to every other part that a change in a particular part causes a changes in all other parts and in the total system"

"For a given system, the environment is the set of all objects outside the system: (1) a change in whose attributes affect the system and (2) whose attributes are changed by the behavior of the system."

"It is hard to say whether increasing complexity is the cause or the effect of man's effort to cope with his expanding environment. In either case a central feature of the trend has been the development of large and very complex systems which tie together modern society. These systems include abstract or non-physical systems, such as government and the economic system. They also include large physical systems like pipe line and power distribution systems, transportation and electrical communication systems. The growth of these systems has increased the need not only for over-all planning, but also for long-range development of the systems. This need has induced increased interest in the methods by which efficient planning and design can be accomplished in complex situations where no one scientific discipline can account for all the factors. Two similar disciplines which emerged about the time of World War II to cope with these problems are called systems engineering and operations research."

"Synthesis of systems is much more difficult. Here science and engineering begin to take on aspects of art. A systems designer or planner not only must construct systems that work harmoniously individually and in tandem, he must also know a lot about the environment that the system is intended to match. Consideration of environmental factors requires foresight and experience; no one can ever foresee all the variables of importance and a choice of which to include is often a difficult one to make."

"In our definition of system we noted that all systems have interrelationships between objects and between their attributes. If every part of the system is so related to every other part that any change in one aspect results in dynamic changes in all other parts of the total system, the system is said to behave as a whole or coherently. At the other extreme is a set of parts that are completely unrelated: that is, a change in each part depends only on that part alone. The variation in the set is the physical sum of the variations of the parts. Such behavior is called independent or physical summativity."

"For any given system, the environment is the set of all objects whose behaviour is influenced by the behaviour of the primary system, and those objects whose behaviour influences the behavior of the primary system."

"Unfortunately, the word "system" has many colloquial meanings, some of which have no place in scientific discussion. In order to exclude such meanings, and at the same time provide a starting point for exposition we state the following definition: A system is a set of objects together with relationships between the objects and between their attributes. Our definition does imply of course that a system has properties, functions or purposes distinct from its constituent objects, relationships and attributes."

"The plan of the present paper is to discuss properties of systems more or less abstractly; that is to define system and to describe the properties that are common to many systems and which serve to characterize them all."

"It is time to employ fractal geometry and its associated subjects of chaos and nonlinear dynamics to study systems engineering methodology (SEM). Systematic codification of the former is barely 15 years old, while codification of the latter began 45 years ago... Fractal geometry and chaos theory can convey a new level of understanding to systems engineering and make it more effective"

"For any given set of objects it is impossible to say that no interrelationships exist."

"Characteristic of our times are the concepts of complexity, growth and change."

"On the personal level, Harold Chestnut is remembered as a quiet but persistent man. Once he determined something ought to be done, he worked until he found a way to make it happen. He viewed life as one large control system that needed to be nudged from time to time to keep it running smoothly and on course. He was a devoted family man who enjoyed hiking and sailing with his family, especially at their cottage on Schroon Lake in the Adirondacks. Harold Chestnut will be long remembered for his technical contributions to the field of systems and control, for his leadership in getting people from divers backgrounds to work together, and for setting up institutions that foster ongoing cooperation for the solution of engineering and societal problems."

"Chestnut's early control work concerned stability issues in electric power systems. The design and manufacturing of electric power system components - generators, transformers, motors, etc. was a major part of GE's activity then and now. During the Second World War Hal moved into aeronautics and ordinance divisions of the company and remained there until 1956. It was in the late 1940s that he wrote his first book. This pace-setting volume established his reputation as a leading figure in the international control community... Following retirement he concentrated on one of his long time passions in the control field - the potential for control concepts to provide insight into problems of international stability. It seems that his dedication to the use of control concepts in societal problems arose from his success in working with wary representatives from many countries to set up IFAC and with proud representatives from various US engineering societies to set up the AACC."

"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."

"Formulating and structuring a system provide methods for relating (1) what the system consists of in the mind of the persons or group desiring it; (2)what it means in terms of the persons or group designing and building it; and (3) in terms of the persons or groups operating, using and servicing it. They provide a set of "reasonable" parts and methods of relating them so that the many persons working on the system can understand the whole in sufficient detail for their purposes, and their particular parts in explicit detail so that they may contribute their best efforts to the extent required. A further purpose of system formulation is to recognize the magnitude of the job, including the possible pitfalls."

"The process of formulating and structuring a system are important and creative, since they provide and organize the information, which each system. "establishes the number of objectives and the balance between them which will be optimized". Furthermore, they help identify and define the system parts. Furthermore, they help identify and define the system parts which make up its "diverse, specialized structures and subfunctions."