🕸Systems Engineering: Systems Thinking (Definitions)

"Systems thinking is a discipline for seeing the 'structures' that underlie complex situations, and for discerning high from low leverage change. That is, by seeing wholes we learn how to foster health. To do so, systems thinking offers a language that begins by restructuring how we think." (Peter Senge, "The Fifth Discipline", 1990)

"Systems thinking is a framework for seeing interrelationships rather than things, for seeing patterns rather than static snapshots. It is a set of general principles spanning fields as diverse as physical and social sciences, engineering and management." (Peter Senge, "The Fifth Discipline", 1990)

"A school of thought that focuses on recognizing the interconnections between the parts of a system and synthesizing them into a unified view of the whole." (Virginia Anderson & Lauren Johnson, "Systems Thinking Basics: From Concepts to Casual Loops", 1997)

"Systems thinking means the ability to see the synergy of the whole rather than just the separate elements of a system and to learn to reinforce or change whole system patterns." (Richard L Daft, "The Leadership Experience", 2002)

"A concept for describing a way of helping people view systems from a wide perspective, seeing overall structures, patterns and cycles in subsystems, rather than seeing only specific events in the main system." (Thomas Hansson, "Communication and Relation Building in Social Systems", 2008)

"Systems thinking is a mental discipline and framework for seeing patterns and interrelationships." (Richard L Daft, "The Leadership Experience", 2008) 

"A manner of thinking that takes into account how the things being studied relate and connect to each other. A key idea embedded in systems theory is that it can assist us in understanding of phenomena and that its holistic emphasis will promote orderly thinking. It is an apt approach to use when thinking about complex issues and interactions." (Deborah W Proctor, "Accessibility of Technology in Higher Education", 2009)

"An approach to analysis, based on the insight that components of a system or (sub)systems may act differently when isolated from the interacting environment and hence the basic concept for studying systems in a holistic way as a supplement to traditional reductionistic techniques." (Herwig Ostermann et al, "Benchmarking Human Resource Information Systems", 2009)

"Critical to this definition is the term ‘interaction’, in that systems thinking is a form of analysis that goes beyond specific causes and effects to the discernment of hidden patterns of behaviors and underlying systemic interrelationships." (Gerald Goodman & Anne Selcer, "Systems Thinking as the Model for Educating Future Healthcare Managers in Information Technology", 2009)

"Is thinking holistically and conscientiously about the world by focusing on the interaction of the parts and their influence within and over the system." (Kambiz E Maani, "Systems Thinking and the Internet from Independence to Interdependence", 2009)

"A holistic concept of tackling problems and events by taking into account the larger scope in the complete environment." (Nashon J Adero et al, "Flow-Based Structural Modelling and Dynamic Simulation of Lake Water Levels", 2011)

"An approach that emphasizes the interconnected nature of the different components that make up a system. Thus, to understand a problem with performance in an organization, you must analyze the whole organizational system not just the component (process, unit or individual) that on the surface seems to be the root of the problem." (Ian Douglas, "Organizational Needs Analysis and Knowledge Management", 2011)

"An approach to understanding the interconnectedness of components when grouped together in order to solve a problem and how the grouped components behave under different stimuli." (Kyle G. Gipson & Robert J Prins, "Materials and Mechanics: A Multidisciplinary Course Incorporating Experiential, Project/Problem-Based, and Work-Integrated Learning Approaches for Undergraduates", 2015)

"In a system dynamics context, a way of thinking based on system dynamics. It is also used to mean system dynamics analyses without quantitative definitions. It focuses on feedback loop structure in order to forecast the direction of performance and find pertinent elements for controlling systems. This is also called qualitative system dynamics." (Yutaka Takahashi, "System Dynamics", 2015)

"Systems thinking is a discipline or process that considers how individual elements interact with one another as part of a whole entity. As an approach to solving problems, systems thinking uses relationships among individual elements and the dynamics of these relationships to explain the behavior of systems such as an ecosystem, social system, or organization." (Karen L Higgins, "Economic Growth and Sustainability: Systems Thinking for a Complex World", 2015)

"The process and understanding of how items influence one another within a whole." (Reginald Wilson, "Outage Analysis and Maintenance Strategies in Hydroelectric Production", 2015)

"A perspective and approach to problem-solving that emphasizes understanding the world in terms of dynamic systems, the interrelationships among elements of systems, and how systems influence each other." (Elisabeth R Gee Kelly M Tran, "Video Game Making and Modding", 2016)

"A relevant scientific instrumentarium, based on principles of General Systems Theory, which uses the systems ideas in order to research and solve complex strategic problems/problem situations." (Dejana Zlatanović et al, "Higher Education Institutions as Viable Systems: A Cybernetic Framework for Innovativeness", 2020)

"The process of understanding how things influence one another. It refers rather to seeing overall structures, patterns and cycles in systems, and the connections between them, than specific events in the system." (The KPI Institute)

🕸Systems Engineering: System Dynamics (Definitions)

"A field of study that includes a methodology for constructing computer simulation models to achieve better under-standing of social and corporate systems. It draws on organizational studies, behavioral decision theory, and engineering to provide a theoretical and empirical base for structuring the relationships in complex systems." (Virginia Anderson & Lauren Johnson, "Systems Thinking Basics: From Concepts to Casual Loops", 1997) 

"A methodology for studying and managing complex feedback systems, such as one finds in business and other social systems." (Lars O Petersen, "Balancing the Capacity in Health Care", 2008)

"System dynamics is a top-down approach for modelling system changes over time. Key state variables that define the behaviour of the system have to be identified and these are then related to each other through coupled, differential equations." (Peer-Olaf Siebers & Uwe Aickelin, "Introduction to Multi-Agent Simulation", 2008) 

"A continuous simulation of systems exhibiting feedback loops. The feedbacks can either intensify activities of the system (positive feedback) or slow them down and stabilize the system (negative feedback)." (Nikola Vlahovic & Vlatko Ceric, "Multi-Agent Simulation in Organizations: An Overview", 2009)

"Is a scientific tool which embodies principles from biology, ecology, psychology, mathematics, and computer science to model complex and dynamic systems." (Kambiz E Maani, "Systems Thinking and the Internet from Independence to Interdependence", 2009)

"System dynamics is an approach to understanding the behaviour of over time. It deals with internal feedback loops and time delays that affect the behaviour of the entire system. It also helps the decision maker untangle the complexity of the connections between various policy variables by providing a new language and set of tools to describe. Then it does this by modeling the cause and effect relationships among these variables." (Raed M Al-Qirem & Saad G Yaseen, "Modelling a Small Firm in Jordan Using System Dynamics", 2010)

[system dynamics simulation:] "A dynamic form of visualization that combines causal loop diagrams and stock and flow diagrams to create a simulation of the workings of a system from one point in time to another." (DAMA International, "The DAMA Dictionary of Data Management", 2011)

"An approach for capturing the complex inter- and intra- dependencies that characterize systems, including feedback over time." (Howard Passell, "Collaborative, Stakeholder-Driven Resource Modeling and Management", 2011)

This studies the non-linear interaction of systems of many connected equations. The approach is based on differential equations. It describes the dynamical properties of a whole system using internal negative and positive feedback loops as well as the use of stocks and flows. (Martin Neumann, "An Epistemological Gap in Simulation Technologies and the Science of Society", 2011)

"A simulation-modelling approach to understand the structure and behaviour of complex dynamic systems over time." (Jaime A Palma-Mendoza, "Hybrid SD/DES Simulation for Supply Chain Analysis", 2014)

"A systems simulation methodology to study complex dynamic behavior of industrial and social systems based on control engineering and cybernetics." (Michael Mutingi & Charles Mbohwa, 2014)

[system dynamics:] "The interactions of connected and interdependent components, which may cause change over time and give rise to interconnected risks; emerging, unforeseeable issues; and unclear, disproportional cause-and-effect relationships." (Project Management Institute, "Navigating Complexity: A Practice Guide", 2014)

"A continuous simulation of systems exhibiting feedback loops. The feedbacks can either intensify activities of the system (positive feedback) or slow them down and stabilize the system (negative feedback)." (Nikola Vlahovic & Vlatko Ceric, "An Overview of Multi-Agent Simulation in Organizations", 2015)

"System Dynamics is a dynamic modelling approach at system level which is primarily used to understand interconnected systems and their evolution over time. Basic elements to represent the systems are internal feedback loops as well as stocks and flows." (Catalina Spataru et al, "Multi-Scale, Multi-Dimensional Modelling of Future Energy Systems", 2015)

"System dynamics [...] uses models and computer simulations to understand behavior of an entire system, and has been applied to the behavior of large and complex national issues. It portrays the relationships in systems as feedback loops, lags, and other descriptors to explain dynamics, that is, how a system behaves over time. Its quantitative methodology relies on what are called 'stock-and-flow diagrams' that reflect how levels of specific elements accumulate over time and the rate at which they change. Qualitative systems thinking constructs evolved from this quantitative discipline." (Karen L Higgins, "Economic Growth and Sustainability: Systems Thinking for a Complex World", 2015)

"A simulation technique based on the solution of differential equations, in which the status variables of a system vary with continuity." (Lorenzo Damiani et al, "Different Approaches for Studying Interruptible Industrial Processes: Application of Two Different Simulation Techniques", 2016)

"A technique que allow to obtain models to explore possible futures or scenarios and ask 'what if' questions in complex situations." (Ruth R Gallegos, "Using Modeling and Simulation to Learn Mathematics", Handbook of Research on Driving STEM Learning With Educational Technologies, 2017)

"A method through which the dynamic behaviour of a complex system over time can be better understood by taking into account internal feedback and time delays." (Henry Xu & Renae Agrey, "Major Techniques and Current Developments of Supply Chain Process Modelling", 2018)

"Computer-aided methodology able to represent the causal structure of a system through stock-and-flow feedback structures and computer simulations regarding the accumulation of materials, information, people, and money." (Francesca Costanza, "Governing Patients' Mobility to Pursue Public Value: A System Dynamic Approach to Improve Healthcare Performance Management", 2018)

"The basis of system dynamics is to understand how system structures cause system behavior and system events." (Arzu E Şenaras, "A Suggestion for Energy Policy Planning System Dynamics", 2018)

🕸Systems Engineering: Systems Theory (Just the Quotes)

"Linking the basic parts are communication, balance or system parts maintained in harmonious relationship with each other and decision making. The system theory include both man-machine and interpersonal relationships. Goals, man, machine, method, and process are woven together into a dynamic unity which reacts." (George R Terry, "Principles of Management", 1960)

"Industrial production, the flow of resources in the economy, the exertion of military effort in a war theater-all are complexes of numerous interrelated activities. Differences may exist in the goals to be achieved, the particular processes involved, and the magnitude of effort. Nevertheless, it is possible to abstract the underlying essential similarities in the management of these seemingly disparate systems." (George Dantzig, "Linear programming and extensions", 1963) 

"The aim of systems theory for business is to develop an objective, understandable environment for decision making; that is, if the system within which managers make the decisions can be provided as an explicit framework, then such decision making should be easier to handle." (Richard A Johnson et al, "Systems Theory and Management", Management Science Vol. 10 (2), 1964)

"System theory is basically concerned with problems of relationships, of structure, and of interdependence rather than with the constant attributes of objects. In general approach it resembles field theory except that its dynamics deal with temporal as well as spatial patterns. Older formulations of system constructs dealt with the closed systems of the physical sciences, in which relatively self-contained structures could be treated successfully as if they were independent of external forces. But living systems, whether biological organisms or social organizations, are acutely dependent on their external environment and so must be conceived of as open systems." (Daniel Katz, "The Social Psychology of Organizations", 1966)

"Clearly, if it is possible to have a self-regulating system that implicitly arranges its own stability, then this is of the keenest management interest." (Anthony S Beer, "Management Science", 1968) 

"The management of a system has to deal with the generation of the plans for the system, i. e., consideration of all of the things we have discussed, the overall goals, the environment, the utilization of resources and the components. The management sets the component goals, allocates the resources, and controls the system performance." (C West Churchman, "The Systems Approach", 1968)

"Perhaps the most important single characteristic of modern organizational cybernetics is this: That in addition to concern with the deleterious impacts of rigidly-imposed notions of what constitutes the application of good 'principles of organization and management' the organization is viewed as a subsystem of a larger system(s), and as comprised itself of functionally interdependent subsystems." (Richard F Ericson, "Organizational cybernetics and human values", 1969) 

"Organizationally what is required - and evolving - is systems management." (Peter Drucker, "MANAGEMENT: Tasks, Responsibilities, Practices", 1973)

"The subject of study in systems theory is not a 'physical object', a chemical or social phenomenon, for example, but a 'system': a formal relationship between observed features or attributes. For conceptual reasons, the language used in describing the behavior of systems is that of information processing and goal seeking (decision making control)." (Mihajlo D Mesarovic & Y Takahara, "Foundations for the mathematical theory of general systems", 1975)

"Systems theory looks at the world in terms of the interrelatedness and interdependence of all phenomena, and in this framework an integrated whole whose properties cannot be reduced to those of its parts is called a system. Living organisms, societies, and ecosystems are all systems." (Fritjof Capra, "The Turning Point: Science, Society, and the Turning Culture", 1982)

"The supposition is prevalent the world over that there would be no problems in production or service if only our production workers would do their jobs in the way that they we taught. Pleasant dreams. The workers are handicapped by the system, and the system belongs to the management." (W Edwards Deming, "Out Of The Crisis", 1982)

"A cardinal principle in systems theory is that all parties that have a stake in a system should be represented in its management." (Malcolm Knowles, "The Adult Learner: A Neglected Species", 1984)

"A manager of people needs to understand that all people are different. This is not ranking people. He needs to understand that the performance of anyone is governed largely by the system that he works in, the responsibility of management." (W Edwards Deming, "The New Economics: For Industry, Government, Education", 1993)

"The prevailing style of management must undergo transformation. A system can not understand itself. The transformation requires a view from outside." (W Edwards Deming, "The New Economics: For Industry, Government, Education", 1993)

More quotes on "Systems Theory" at the-web-of-knowledge.blogspot.com. 

🕸Systems Engineering: Entropy (Definitions)

"The Entropy of a system is the mechanical work it can perform without communication of heat, or alteration of its total volume, all transference of heat being performed by reversible engines." (James C Maxwell, "Theory of Heat", 1899)

"Entropy is the measure of randomness." (Lincoln Barnett, "The Universe and Dr. Einstein", 1948)

"Entropy is a measure of the heat energy in a substance that has been lost and is no longer available for work. It is a measure of the deterioration of a system." (William B. Sill & Norman Hoss (Eds.), "Popular Science Encyclopedia of the Sciences", 1963)

"Entropy [...] is the amount of disorder or randomness present in any system." (Lars Skyttner, "General Systems Theory: Ideas and Applications", 2001)

"A measurement of the disorder of a data set." (Glenn J Myatt, "Making Sense of Data: A Practical Guide to Exploratory Data Analysis and Data Mining", 2006)

"[...] entropy is the amount of hidden microscopic information." (Leonard Susskind, "The Black Hole War", 2008)

"A measure of the uncertainty associated with a random variable. Entropy quantifies information in a piece of data." (Radu Mutihac, "Bayesian Neural Networks for Image Restoration" [in "Encyclopedia of Artificial Intelligence", 2009)

"Measurement that can be used in machine learning on a set of data that is to be classified. In this setting it can be defined as the amount of uncertainty or randomness (or noise) in the data. If all data is classified with the same class, the entropy of that set would be 0." (Isak Taksa et al, "Machine Learning Approach to Search Query Classification", 2009)

"A measure of uncertainty associated with the predictable value of information content. The highest information entropy is when the ambiguity or uncertainty of the outcome is the greatest." (Alex Berson & Lawrence Dubov, "Master Data Management and Data Governance", 2010)

"Refers to the inherent unknowability of data to external observers. If a bit is just as likely to be a 1 as a 0 and a user does not know which it is, then the bit contains 1 bit of entropy." (Mark S Merkow & Lakshmikanth Raghavan, "Secure and Resilient Software Development", 2010)

"The measurement of uncertainty in an outcome, or randomness in a system." (DAMA International, "The DAMA Dictionary of Data Management", 2011)

"A metric used to evaluate and describe the amount of randomness associated with a random variable."(Wenbing Zhao, "Increasing the Trustworthiness of Online Gaming Applications", 2015)

"Anti-entropy is the process of detecting differences in replicas. From a performance perspective, it is important to detect and resolve inconsistencies with a minimum amount of data exchange." (Dan Sullivan, "NoSQL for Mere Mortals®", 2015)

"Average amount of information contained in a sample drawn from a distribution or data stream. Measure of uncertainty of the source of information." (Anwesha Sengupta et al, "Alertness Monitoring System for Vehicle Drivers using Physiological Signals", 2016)

"In information theory this notion, introduced by Claude Shannon, is used to express unpredictability of information content. For instance, if a data set containing n items was divided into k groups each comprising n i items, then the entropy of such a partition is H = p 1 log( p 1 ) + … + p k log( p k ), where p i = n i / n . In case of two alternative partitions, the mutual information is a measure of the mutual dependence between these partitions." (Slawomir T Wierzchon, "Ensemble Clustering Data Mining and Databases", 2018) [where i is used as index]

"Entropy is a measure of amount of uncertainty or disorder present in the system within the possible probability distribution." ("G Suseela & Y Asnath V Phamila, "Security Framework for Smart Visual Sensor Networks", 2019)

"Lack of order or predictability; gradual decline into disorder." (Adrian Carballal et al, "Approach to Minimize Bias on Aesthetic Image Datasets", 2019)

"It is the quantity which is used to describe the amount of information which must be coded for compression algorithm." (Arockia Sukanya & Kamalanand Krishnamurthy, "Thresholding Techniques for Dental Radiographic Images: A Comparative Study", 2019)

"In the physics - rate of system´s messiness or disorder in a physical system. In the social systems theory - social entropy is a sociological theory that evaluates social behaviors using a method based on the second law of thermodynamics." (Justína Mikulášková et al, "Spiral Management: New Concept of the Social Systems Management", 2020)

🕸Systems Engineering: Cybernetics (Definitions)

"Cybernetics […] combines under one heading the study of what in a human context is sometimes loosely described as thinking and in engineering is known as control and communication. In other words, cybernetics attempts to find the common elements in the functioning of automatic machines and of the human nervous system, and to develop a theory which will cover the entire field of control and communication in machines and in living organisms." (Norbert Wiener, "Cybernetics", 1948)

The 'cybernetics' of Wiener […] is the science of organization of mechanical and electrical components for stability and purposeful actions." (Qian Xuesen, "Engineering Cybernetics", 1954) 

"[Cybernetics is] the art of ensuring the efficacy of action." (Louis Couffignal, 1958)

"Cybernetics is the science of the process of transmission, processing and storage of information." (Sergei Sobolew, Woprosy Psychology, 1958)

"Cybernetics is the general science of communication. But to refer to communication is consciously or otherwise to refer to distinguishable states of information inputs and outputs and /or to information being processed within some relatively isolated system." (Henryk Greniewski, "Cybernetics without Mathematics", 1960)

"Cybernetics is the science or the art of manipulating defensible metaphors; showing how they may be constructed and what can be inferred as a result of their existence." (Gordon Pask, "The Cybernetics of Human Performance and Learning", 1966)

"Cybernetics is concerned with scientific investigation of systemic processes of a highly varied nature, including such phenomena as regulation, information processing, information storage, adaptation, self-organization, self-reproduction, and strategic behavior. Within the general cybernetic approach, the following theoretical fields have developed: systems theory (system), communication theory, game theory, and decision theory." (Fritz B Simon et al, "Language of Family Therapy: A Systemic Vocabulary and Source Book", 1985)

"Cybernetics is the science of effective organization, of control and communication in animals and machines. It is the art of steersmanship, of regulation and stability. The concern here is with function, not construction, in providing regular and reproducible behaviour in the presence of disturbances." (Chris Lucas, "Cybernetics and Stochastic Systems", 1999)

"Cybernetics is the study of systems and processes that interact with themselves and produce themselves from themselves." (Louis Kauffman, 2007)

"Cybernetics is the art of creating equilibrium in a world of possibilities and constraints." (Ernst von Glasersfeld, "Partial Memories: Sketches from an Improbable Life", 2010)

"Cybernetics is the study of systems which can be mapped using loops (or more complicated looping structures) in the network defining the flow of information. Systems of automatic control will of necessity use at least one loop of information flow providing feedback." (Alan Scrivener, "A Curriculum for Cybernetics and Systems Theory", 2012)

🕸Systems Engineering: Chaos Theory (Definitions)

"A scientific approach – research effort which is based on examining behaviors of nonlinear dynamical systems, which are highly sensitive to their initial conditions." (Utku Köse & Ahmet Arslan, "Chaotic Systems and Their Recent Implementations on Improving Intelligent Systems", 2014)

"Study of deterministic behaviours that depend on initial conditions in physical, natural and social sciences." (Ayşe G Gözüm, "Evaluating HRM Functions within the Context of Chaos and Complexity Theory", 2016)

"The mathematical framework for understanding irregular and erratic fluctuations in economic cycles, financial markets, weather, other complex phenomenon, or non-linear systems with many variables." (Kijpokin Kasemsap, "Utilizing Complexity Theory and Complex Adaptive Systems in Global Business", 2016)

"The study of the behavior of dynamical systems that are highly sensitive to initial conditions." (Rohnn B Sanderson, "Understanding Chaos as an Indicator of Economic Stability", 2016)

"The theory that emerged from mathematics and used widely by other disciplines which concentrates on the dynamical systems." (Çağlar Doğru, "Leader-Member Exchange and Transformational Leadership in Chaos and Complexity", 2016)

"A field of study that explains nonlinear or dynamical systems." (Sharon E Norris, "Examining the Strategic Leadership of Organizations Using Metaphor: Brains and Flux-Interconnected and Interlocked", 2017)

"Chaos theory is the branch of mathematics deals with complicated linear dynamic systems." (Anandkumar R &  Kalpana R, "A Review on Chaos-Based Image Encryption Using Fractal Function", 2020)

"Suggests a randomness of understanding around complex patterns. These may be described as dynamic systems that reflect irregularities and is extremely sensitive to negligible fluctuations or moderations in situation." (Caroline M Crawford et al, "Social Learning Through a Participative Storytelling Framework: Rethinking the Essence of Course Engagement", 2021)

"Chaos theory is a branch of mathematics focusing on the study of chaos - dynamical systems whose random states of disorder and irregularities are governed by underlying patterns and deterministic laws that are highly sensitive to initial conditions." (Nima Norouzi, "Criminal Policy, Security, and Justice in the Time of COVID-19", 2022)

🕸Systems Engineering: Complex Systems (Definitions)

"Roughly, by a complex system I mean one made up of a large number of parts that interact in a nonsimple way." (Herbert Simon, "The Architecture of Complexity", Proceedings of the American Philosophical Society Vol. 106 (6), 1962)

"A complex system is one which possesses mathematical images which are not dynamical systems." (Robert Rosen, On complex systems, European Journal of Operational Research Vol. 30 (2), 1987)

"A complex system is a system formed out of many components whose behavior is emergent, that is, the behavior of the system cannot be simply inferred from the behavior of its components." (Yaneer Bar-Yamm, "Dynamics of Complexity", 1997)

"A system may be called complex here if its dimension (order) is too high and its model (if available) is nonlinear, interconnected, and information on the system is uncertain such that classical techniques can not easily handle the problem." (M Jamshidi, Autonomous Control on Complex Systems: Robotic Applications, Current Advances in Mechanical Design and Production VII, 2000)

"A highly coupled system where the outcomes of the system are the result of the interactions that occur between its different components." (David Lyell et al, "Health Systems Simulation", Encyclopedia of Healthcare Information Systems, 2008)

"Network-based systems characterized by feedback-driven flow of information, openness, self-organization, and emergence. (Ani Calinescu & Janet Efstathiou, "Measures of Network Structure", Encyclopedia of Networked and Virtual Organizations, 2008) 

"[a complex system is] a system in which large networks of components with no central control and simple rules of operation give rise to complex collective behavior, sophisticated information processing, and adaptation via learning or evolution." (Melanie Mitchell, "Complexity: A Guided Tour", 2009)

"Systems made of several interconnected simple parts which altogether exhibit a high degree of complexity from each emerges a higher order behaviour." (Radu Mutihac, "Mathematical Modeling of Artificial Neural Networks", Encyclopedia of Artificial Intelligence, 2009)

"CS [complex system] is a system composed of many heterogeneous agents, which are nonlinearly interconnected, while the final emergence of the system is completely different than the individual element`s performance." (Shahrooz V Manesha & Massimo Tadi, "Sustainable urban morphology emergence via complex adaptive system analysis: sustainable design in existing contex", Procedia Engineering 21, 2011)

"A system that exhibits a mutual interdependency of components and for which a change in the input parameter(s) can result in a non-proportional large or small change of the system output." (Alexander Kolker, Management Science for Healthcare Applications, Encyclopedia of Business Analytics and Optimization, 2014) 

"A system whose intricacy impedes the forecasting of its behaviour." (Valentina M Ghinea, "Modelling and Simulation of the Need for Harmonizing the European Higher Education Systems", Handbook of Research on Trends in European Higher Education Convergence, 2014)

"A system which is usually composed of large number of possibly heterogeneous interacting agents, which are seen to exhibit emergent behavior." (Stephen E Glavin & Abhijit Sengupta, "Modelling of Consumer Goods Markets: An Agent-Based Computational Approach", Handbook of Research on Managing and Influencing Consumer Behavior, 2015)

"Complex systems are networks made of a number of components that interact with each other, typically in a nonlinear fashion. Complex systems may arise and evolve through self-organization, such that they are neither completely regular nor completely random, permitting the development of emergent behavior at macroscopic scales." (Hiroki Sayama, "Introduction to the Modeling and Analysis of Complex Systems", 2015)

"The occurrence of new phenomena generated unpredictably by the interaction of simple rules and individual mechanisms that are in constant flux and interaction. Emergence suggests something novel is perpetually emerging at a systems/global level as the world and environment constantly shifts and changes at a mechanistic/local level." (Kathy Sanford & Tim Hopper, "Digital Media in the Classroom: Emergent Perspectives for 21st Century Learners", Handbook of Research on Digital Media and Creative Technologies, 2015)

"A system characterized by the number of the elements that constitute it, and by the nature of the interactions between these elements." (Manuela Piscitelli, "Application of Complexity Theory in Representation of the City", Handbook of Research on Chaos and Complexity Theory in the Social Sciences, 2016)

"A complex system means a system whose perceived complicated behaviors can be attributed to one or more of the following characteristics: large number of element, large number of relationships among elements, non-linear and discontinuous relationship, and uncertain characteristics of elements." (Chunfang Zhou, "Fostering Creative Problem Solvers in Higher Education: A Response to Complexity of Societies", Handbook of Research on Creative Problem-Solving Skill Development in Higher Education, 2017)

"System made up of many interconnected elements on various levels; interactions on lower levels give rise to events on higher levels." (Naomi Thompson & Joshua Danish, "Designing BioSim: Playfully Encouraging Systems Thinking in Young Children", Handbook of Research on Serious Games for Educational Applications, 2017)