to the death of bacteria under the influence of light or disinfectants, to the consumptions of an animal by starvation, and to the decrease of an animal or human population where death rate is higher than birth rate.” The discovery of this phenomenon of “isomorphy of laws” in the different scientific fields caused Ludwig von Bertalanffy to aim for a “Unity of Science” with help of the “General System Theory.” It was apparent to him that this ambitious goal could only be achieved — if ever — in the inscrutable future.
His proceeding is marked mathematically. A standardization of the sciences is finally seen by him as the
“reduction of all science to physics, in the final resolution of all phenomena into physical events.”
The system approach of cybernetics (Wiener, 1961) was developed at about the same time as the
“General System Theory.” This approach is likewise mathematically formed. Wiener and others under- stand cybernetics (Greek: “kybernetes”¼steermanship) as the “entire field of control and communi- cation theory, whether in the machine or in the animal” (Wiener, 1961). The cybernetics takes up concepts of feedback, regulation, and control and interprets social systems in a cybernetic way.
Methods, procedures, and realizations of the (automatic) control engineering are generalized and applied to nontechnical concepts. A process is described with the control loop, which functions auton- omously on the basis of the exact given premises. A desired value is given to the system. If it comes to a disturbance, the system implements prior defined corrections autonomously, in order to achieve the pro- grammed specified condition again. The system compensates any environmental changes with self change. It experiences information about required changes via feedback of the results of its procedures.
Figure 5.1 shows an example of a control loop with reference to the handling of a boat (Frank, 1964). The boat can be interpreted as a socio-technical system. The captain formulates the destination. The pilot determines the particular location (current status) and composes a program to transfer the current status to the desired status. He has to “save” the desired status, to measure the current status, to compare the two values and to derive a program. This program has to be conveyed to the steersman by the pilot in terms of individual decisions (so-called “determined” decisions). The steersman transfers these orders into navigation positions.
Self-regularization, adaptation, and learning aptitude are, therefore, system specifications, which are examined by the cybernetics. The cybernetics discusses for the first time the relationship between system and environment as a problem of constancy and change. In the center of the considerations the question is formed, how system constancy can be maintained in a changing environment. For the
captain destination
pilot
data processing and planning
steersman steering
rower/ power engine working physically
environment actual
situation
target situation
FIGURE 5.1 The socio-technical system “boat” as an example of a control loop.
Humans in Work System Environment 5-3
first time, the stability of a system was not defined as a trait of systems (ontological approach) but as a problem, which has to be solved perpetually (Luhmann, 1973).
An integration of the “General System Theory” and the cybernetics to a system-theoretical-cybernetic concept began for the first time with Ashby (1956). He uses the “Black Box theory” to describe the relations between an experimenter and his environment with special attention to the flow of information.
“The primary data of any investigation of a Black Box consists of a sequence of values of the vector with two components: input state, output state” (comparable to cybernetics). Referring to the “General System Theory,” two machines are isomorphic, “if a one – one transformation of the states (input and output) of the one machine into those of the other can convert the one representation to the other.”
Thus, Ashby explains the fundamentals of cybernetics: the processes within the system and the processes of communication between system and system. Those are important to study the central theme of cybernetics — regulation and control. Regulation is essentially related to the flow of variety; without regulation the variety is large — with regulation it is small.
In the meantime it emerged that various impulses for individual scientific fields proceeded from the system-theoretical-cybernetic concept. However, their requirement to promote a standardization of science in different material systems with the help of a discipline-spreading terminology and the assumed existence of a more formal structure, that is, isomorphic laws, can only be partly fulfilled. In fact system approaches and theories were developed by the single branches of science. These consider the specific questions of the individual scientific field and contain the respective specialized terminology.
The system-theoretical-cybernetic approach proceeds from a “shortened” idea of man. Humans are understood less as socio-emotional nature, which would like to carry out individual motives and needs. Rather, humans are regarded as a self-regulating system, which compensates for environmental changes by self changes. Despite this “shortened” idea of man, the view of humans is of importance as automatic controller for the understanding of human data processing. Related to man – machine systems a regulation-technical model can appear in such a way that humans function as an automatic controller and the object, which can be regulated is represented by the machine. The goal value is given from the “outside.” The task of the automatic control loop consists of adapting the output quantity (actual value) as precisely as possible to the target value.
5.2.2 Socio-Technical System Approach
The socio-technical system approach — originating from social psychology — dates back particularly to a set of studies of the London Tavistock Institute of Human Relations. A study accomplished in English coal mines forms the starting point for the development of the socio-technical system approach (Trist and Bamforth, 1951). The Tavistock Institute was assigned to determine the causes for the low work motivation of the workers, for the high absence and fluctuation rates, as well as for a high number of accidents and labor disputes in a coal pit. A cause for the problems formed the introduction of the “long- wall method of coal-getting.” The researchers found out that in the course of the introduction of this half-mechanized digging method existing social structures were destroyed. Thus, before the introduction of this “mass-production engineering” the complete coal-getting task — consisting of digging, loading, transport etc — was accomplished by a “single, small, face-to-face group, which experiences the entire cycle of operations within the compass of its membership.” These shift-spreading groups divided their wages in the same proportion among themselves and were responsible also for their security. “Leadership and
‘supervision’ were internal of the group, which had a quality of responsible autonomy.” With the introduc- tion of the longwall method the groups were dissolved and the holistic task was divided into subtasks, trans- ferred to specialists and spread over shifts. Trist and Bamforth (1951) could show that these changes had a negative effect on work motivation. In doing so the joint founders of the socio- technical system approach stress the dependence of social and structural aspects of an organization on the applied technology.
In consequence further investigations were accomplished concerning the socio-technical system approach.
The fundamental system-theoretical theses of the socio-technical system approach can be summarized as the following (Emery, 1972; Rohmert and Weg, 1976; Alioth, 1980; Antoni, 1996; Ulich, 2001):
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Organizations are open, dynamic, and goal-oriented systems, which consist of a social and a technical subsystem. The social subsystem of an organization contains the employees with their knowledge and abilities, as well as their individual and group-specific needs. The technical subsystem contains the entirety of the technical and spatial conditions of work (Figure 5.2).
In order to avoid suboptimal results of system design, technical and social subsystems have to be opti- mized together. The socio-technical system approach acts on the assumption that technology has a crucial influence on the organization. However, the organization is not completely determined by the technology.
Also with a given technical system organizational options exist. This clearance of system design, obviously, increases, if the technical system and the work organization are planned together. When planning, the needs and requirements of the coworkers in reference to their work are to be considered.
The system “enterprise” is subject to fluctuations. These are caused, on the one hand, by the system environment (e.g., changes of demand). On the other hand, system fluctuations also have internal causes (e.g., disturbance at a machine; necessary reworking measures due to errors during the work execution). A central thesis of the socio-technical system approach proves that enterprises with small decentralized, self-regulating organizational units are more able to adapt to changes and fluctuations than central-controlled systems.
With the design of self-regulating organizational units there are three principles to consider (Ulich, 2001): (1) The formation of organizational units, which are relatively independent from each other should prevent the fluctuations and disturbances propagating uncontrollably. (2) An internal task coherent of an organizational unit makes it possible for the coworkers to determine their operational procedure on their own. This design principle stresses the motivational aspects of holistic tasks. (3) The design of the organization should be product-orientated, if possible. Thus, the formation of independent organizational units is supported. Furthermore, the work task shows a stronger connection with the product.
The socio-technical system approach raises the claim to provide a theoretical reference framework for the analysis of practical problems in organizations. Sydow (1985) shows that the socio-technical system approach only partly comes up to its claim. He justifies his animadversion on the approach among other things with the fact that central constructs like the one of the technical and that of the social system, their connection to the task system and to the feeling-orientated system are formulated imprecisely. Beyond that he shows that, many a time, technology is accepted as fixed although the necessity for a common optimization of the technical and social system is continually stressed.
The idea of man based on the socio-technical system approach refers particularly to the motive struc- ture of humans (Sydow, 1985). The focus of attention is the effect of the work task on humans and their motivation. The socio-technical system approach focuses on intrinsic motives of humans. It shows that
socio-technical system
technical sub-system working equipment technical conditions spatial conditions
social sub-system
employees with their know- ledge, abilities and their individual and group-specific needs
task of the system
FIGURE 5.2 Elements of the socio-technical system (in modification of Ulich, E., Arbeitspsychologie, 5th ed., Scha¨effer-Poeschel, Stuttgart, 2001. With Permission).
Humans in Work System Environment 5-5
humans are regarded in a social nature. Expectations and needs of humans are, therefore, to be con- sidered with the design of work organization and technical system. The economic orientation of humans, which manifests itself in their interest in a maximum payment is played down despite differing project experiences of the Tavistock researchers (Kelly, 1978; Sydow, 1985).
Despite the aforementioned animadversion on the socio-technical system approach it is very import- ant from an ergonomic view as the principle of optimizing the social and technical system together cor- responds with ergonomic aims. Beyond that, it has to be emphasized that small, decentralized organizational units, according to the socio-technical system approach, in particular correspond with today’s requirements of high flexibility and short response and lead times in production.
5.2.3 Evolution-Theoretical Approach
The evolution - theoretical approach — originating from biology — closely follows the evolution theory of Darwin. The subject matter of the evolution theory is the adaptation of organisms to their environ- ment after periods of time.
According to Maturana and Varela (1987), reproduction is the characteristic of an organism and is differentiated into heredity transmission and reproductive variation. Heredity transmission means that structural similarities arise, which already belong to the preceding generations. Variations in trans- missions are the differences, which show up in the course of the development and can explain the diver- sity of species. The process of structural changing of a unit without a loss of their basic organization is called ontogenesis. This structural change takes place in each instant. It is released either by interactions with the surrounding environment or as result of the internal dynamics of a unit. This change ends only with the dissolution of a unit.
During the interactions between the organism and its environment the disturbances in the environ- ment do not determine what happens to the organism. Rather, the structure of the organism determines what kind of change happens within it as a result of the disturbances.
As long as the unit does not interact destructively with the environment, compatibility can be found between the environment and the unit. In this case, environment and unit act as sources of disturbances in a mutual status and cause changes in each other. This constant process is called structural coupling.
The basis of the continuity of organisms is the structural compatibility of the organism with the environ- ment. This is also called adaptation. The adaptation of a unit to its environment is a necessary conse- quence of the structural coupling of this unit with its environment.
Necessary conditions for the existence of an organism are preservations of autopoiesis and adaptation.
Autopoiesis in this context means that an organism strives for producing itself continuously. Lines of descent threatened by extinction can, therefore, be explained by not having the ability to adapt suffi- ciently. Basic principles of the evolution-theoretical approach are depicted in Figure 5.3.
1. Heredity transmission: structural similarities, which already belong to the preceding generations of a system arise
2. Variation in transmission: differences, which show up in the course of the development and can be explained by the adaptation and diversity of species
3. Selection: resources are rare; a lack of adaptation of a system to their environment results in finishing of system existence. The more resources in system environment exist the greater is the chance to survive.
FIGURE 5.3 Basic principles of the evolution-theoretical approach.
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Based on this biological point of view, Malik (1993) transferred the evolution-theoretical approach to the management of enterprises. The main issue of importance for enterprises is their adaptability to unforeseeable changes. This ability becomes particularly important in times of difficult economic situ- ations, in order to increase the probability of survival. On the one hand, the goal is to avoid behavior, which disturbs or endangers a system. On the other hand, the goal is to take over useful changes. The evolution-theoretical approach was also transferred to the theory of social systems (Section 5.2.5).
Autopoiesis in the context of social systems means that they strive continuously to maintain their sense (Krieger, 1996).
Critics of the evolution-theoretical approach provide examples, which this theory does not apply to (Krieger, 1996). On the level of individuals, political or religious martyrs of all kinds show that for humans the preservation of an idea (thus, a certain form of sense) can be more important than the pres- ervation of the own life. The same applies to believers who do not touch animals and plants because of religious taboo, although they are threatened by starvation.
Humans are to be considered primarily of a biological, rather, than of a socio-emotional nature in the evolution-theoretical approach. Humans are part of the evolution and their task consists of the best poss- ible adaptability to their environment. According to this theory, humans act because of self-preservation.
5.2.4 Engineering-Scientific System Approaches
The system theory in engineering science developed, on the one hand, a firmly established basic subject.
On the other hand, the system approach was integrated into single engineering-scientific subjects in different ways, which is shown through examples of measurement and control engineering, design engin- eering, manufacturing technique, thermodynamics, and rationalization research.
In measurement and control engineering methodology is usually based upon the preposition of math- ematical models, in order to win insights into technical connections with different applications and to obtain quantitative results. The models mentioned represent mathematical pictures for the interaction of the physical features, which are the basis for the technical procedures. The advantage of the application of the system theory is regarded by the fact that a multiplicity of features in measurement and control engineering can be explained as a consequence of a few system-theoretical basic concepts (Unbehauen, 1990).
In design engineering, technical objects such as facilities, apparatuses, machines, devices, and individ- ual parts are considered as artificial systems. These consist of an entirety of elements, which are arranged and due to their characteristics linked with one another by relations. Technical systems serve a process in which energies, materials, and signals are led and/or changed (Pahl, 1995). Design engineering proceeds from a conventional system understanding. Such a system is distinguished from its environment. Con- nections to the environment are formed by input and output variables. A system can be subdivided into subsystems. A clutch, for example, represents a component within a machine while it can be divided into the two subsystems “flexible clutch” and “shift clutch” again as independent components. The subsys- tems can be divided again into individual elements of the system.
A manufacturing system has the purpose to fulfill a fixed task of manufacturing (Warnecke, 1995).
Therefore, coordinated processes are necessary. These are generated by subsystems of the manufacturing system (Figure 5.4). Among these subsystems are the control system, the power-supply-system, the handling-of-work-pieces-system, the tool-handling-system, the measuring-and-control-system, the auxiliary-supplies-system, as well as the disposal system. The basic task of manufacturing is fulfilled in the subsystem “work system.”
A thermodynamic system is understood as a material formation whose thermodynamic characteristics are examined (Stephan, 1995). Examples of thermodynamic systems are a mass of gas, a liquid and its steam, a mixture of several liquids, or a crystal. A thermodynamic system has a system border, which can shift, however, during the procedure, for example, by expansion of gas. Furthermore, the distinction between open and closed systems is of importance in thermodynamics. Closed systems are impermeable for matter. Open systems can change their mass, if masses flowing in and leaking out are unequal.
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In the rationalization research, concepts of the cybernetics, synergetic, and complexity theory were taken up (Luczak and Fricker, 1996). The situation of the rationalization is formed by increasing the dynamics of changes, which makes shorter response times necessary and causes an increasing complex- ity of operational settings of tasks. For the operational rationalization in principle the question is derived whether the solution is to be searched in the decrease and avoidance of complexity or in better methods of its handling and control (Warnecke and Hueser, 1995). Approaches, which aim at excluding a decrease of complexity of operational structures are not regarded as sufficient, however, for a successful complexity management since usually only short-term efficiency advantages are achieved for the disadvantage of long-term stability (Bullinger et al., 1993). In terms of the complexity accomplishment, on the one hand, the connection between operational structures and the system beha- vior is regarded (Malik, 1992). The question arises how operational structures are to be arranged.
On the other hand, the behavior of the involved people during problem release processes is examined.
For the design of problem solution processes various realizations and experiences are present.
Regarding the modeling and design of order structures, however, few approaches are present. There- fore, an instrument was developed and evaluated for the modeling and design of complex production structures (Luczak and Fricker, 1996; Fricker, 1996). As degrees of complexity, variety (Ashby, 1956), entropy (Shannon, 1976), and the effective complexity (Gell-Mann, 1994) are used. The developed instru- ment enables the following:
. Representation and quantitative evaluation of interlaced operational coherences and order struc- tures in the sense of monitoring the structural development
. Evaluation of the operational complexity, the partial equilibrium, and the adaptability to defined and internal measuring points
. Identification of operational complexity drivers and of starting points for reorganization measures
. Quantification of order and organizational structures.
control system
handling-of- workpieces- system
measuring- and-control- system
“work system” tool-handling- system
power-supply-system disposal
system
auxiliary- supplies- system information
raw material/
semi- finished products finished products
waste
materials auxiliary
supplies tools
energy material
energy information
FIGURE 5.4 Functional structure of the manufacturing system (in modification of Warnecke, H.-J.,Dubbel- Taschenbuch fu¨r den Maschinenbau, 18th ed., Springer, Berlin, 1995. With permission.)
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