Book•
Complex Adaptive Systems: An Introduction to Computational Models of Social Life
01 Jan 2007-
TL;DR: This book is not a textbook, but rather an essay on complex adaptive systems, and the best method to discover their properties is to dispatch many computer agents to experience the system’s possibilities.
Abstract: Theoretical physics is replete with models. When equations of motion are not available, or not amenable to perturbation theory, or just too hard from which to extract useful information, then physicists turn to models and computation. The Ising model of ferromagnetism is a classic example. A simple nearest neighbor temperature dependent interaction, in two or more dimensions, leads to long-range order and a phase transition at a finite temperature. This model has many locally interacting parts and an emergent behavior (ferromagnetism) at a critical temperature. However, the system never adapts. It does not change the phase transition to a higher temperature or avoid a phase transition altogether. Social systems are always adapting, and this interesting twist produces a vast array of possibilities and forms the basis of much of the discussion in Miller and Page’s book. This book is not a textbook, but rather an essay on complex adaptive systems. The discussions and insights will be better appreciated by readers who have already tried their hand at investigating complex adaptive systems. These systems can be so complex that the best method to discover their properties is to dispatch many computer agents to experience the system’s possibilities. The study becomes more interesting when the agents can alter their actions and the rules of the game. Miller and Page give the simple, but instructive example of forest growth and lightning induced forest fires. If trees grow too rapidly they will cover the allowable space and a fire started anywhere in the forest will spread and destroy the entire forest. A very slow growth will only produce a sparse forest. The authors find a tree growth rate to achieve an optimal stable high forest coverage. Their solution is trumped when altruistic agents are introduced, one for each tree. Some of the agents adapt by not growing a tree in their plot of land (to their personal disadvantage) but the overall global organization is one of firebreaks preventing large scale fires. Adaptation wins! Another model discussed is what physicists call the minority game, that is, making a choice that puts you in the minority. This is perhaps best known through the El Faro example of choosing whether or not to go to Santa Fe’s El Faro bar tonight based on whether it was
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TL;DR: In this article, the authors develop a conceptual framework addressing the dynamics and adaptive capacity of resource governance regimes as multi-level learning processes, where the influence of formal and informal institutions, the role of state and non-state actors, the nature of multilevel interactions and the relative importance of bureaucratic hierarchies, markets and networks are identified as major structural characteristics of governance regimes.
Abstract: Governance failures are at the origin of many resource management problems. In particular climate change and the concomitant increase of extreme weather events has exposed the inability of current governance regimes to deal with present and future challenges. Still our knowledge about resource governance regimes and how they change is quite limited. This paper develops a conceptual framework addressing the dynamics and adaptive capacity of resource governance regimes as multi-level learning processes. The influence of formal and informal institutions, the role of state and non-state actors, the nature of multi-level interactions and the relative importance of bureaucratic hierarchies, markets and networks are identified as major structural characteristics of governance regimes. Change is conceptualized as social and societal learning that proceeds in a stepwise fashion moving from single to double to triple loop learning. Informal networks are considered to play a crucial role in such learning processes. The framework supports flexible and context sensitive analysis without being case study specific. First empirical evidence from water governance supports the assumptions made on the dynamics of governance regimes and the usefulness of the chosen approach. More complex and diverse governance regimes have a higher adaptive capacity. However, it is still an open question how to overcome the state of single-loop learning that seem to characterize many attempts to adapt to climate change. Only further development and application of shared conceptual frameworks taking into account the real complexity of governance regimes can generate the knowledge base needed to advance current understanding to a state that allows giving meaningful policy advice.
1,783 citations
Cites background from "Complex Adaptive Systems: An Introd..."
...Modular system structure and decentralized control lead to higher degree of adaptiveness and robustness of a system (Pahl-Wostl, 1995; Miller and Page, 2007)....
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TL;DR: This work was funded by a grant from The Health Foundation (London, UK) that supported HR, KG, and NS.
693 citations
Cites background from "Complex Adaptive Systems: An Introd..."
...Techniques from other disciplines that are more advanced in complex systems methodologies, such as economics, climate change, and urban science, also need to be adopted and adapted.(30,31)...
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TL;DR: The developments and the research trends in coordination with the CAVs that have been reported in the literature to date are summarized and remaining challenges and potential future research directions are discussed.
Abstract: Connected and automated vehicles (CAVs) have the potential to improve safety by reducing and mitigating traffic accidents. They can also provide opportunities to reduce transportation energy consumption and emissions by improving traffic flow. Vehicle communication with traffic structures and traffic lights can allow individual vehicles to optimize their operation and account for unpredictable changes. This paper summarizes the developments and the research trends in coordination with the CAVs that have been reported in the literature to date. Remaining challenges and potential future research directions are also discussed.
685 citations
Cites background from "Complex Adaptive Systems: An Introd..."
...In this direction, complex systems theory [95] appears to be a viable framework for modeling and analysis....
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TL;DR: This paper concludes by advocating development of more process-based decision models as well as protocols or architectures that facilitate better modeling of human decisions in various CHANS.
629 citations
Book•
01 Apr 2012
TL;DR: Because employers bear direct medical and indirect productivity costs of obesity, they can benefit from promoting and increasing physical activity, healthy eating, breastfeeding, and overall well-being in the workplace.
Abstract: One-third of adults are now obese, and children's obesity rates have climbed from 5 to 17 percent in the past 30 years. The causes of the nation's obesity epidemic are multi-factorial, having much more to do with the absence of sidewalks and the limited availability of healthy and affordable foods than a lack of personal responsibility. The broad societal changes that are needed to prevent obesity will inevitably affect activity and eating environments and settings for all ages. Many aspects of the obesity problem have been identified and discussed; however, there has not been complete agreement on what needs to be done to accelerate progress. Accelerating Progress in Obesity Prevention reviews previous studies and their recommendations and presents five key recommendations to accelerate meaningful change on a societal level during the next decade. The report suggests recommendations and strategies that, independently, can accelerate progress, but urges a systems approach of many strategies working in concert to maximize progress in accelerating obesity prevention.The recommendations in Accelerating Progress in Obesity Prevention include major reforms in access to and opportunities for physical activity; widespread reductions in the availability of unhealthy foods and beverages and increases in access to healthier options at affordable, competitive prices; an overhaul of the messages that surround Americans through marketing and education with respect to physical activity and food consumption; expansion of the obesity prevention support structure provided by health care providers, insurers, and employers; and schools as a major national focal point for obesity prevention. The report calls on all individuals, organizations, agencies, and sectors that do or can influence physical activity and nutrition environments to assess and begin to act on their potential roles as leaders in obesity prevention.
600 citations
References
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TL;DR: The authors show that the Musgrave-Samuelson analysis, which is valid for federal expenditures, need not apply to local expenditures, and restate the assumptions made by Musgrave and Samuelson and the central problems with which they deal.
Abstract: NE of the most important recent developments in the area of "applied economic theory" has been the work of Musgrave and Samuelson in public finance theory.2 The two writers agree on what is probably the major point under investigation, namely, that no "market type" solution exists to determine the level of expenditures on public goods. Seemingly, we are faced with the problem of having a rather large portion of our national income allocated in a "non-optimal" way when compared with the private sector. This discussion will show that the Musgrave-Samuelson analysis, which is valid for federal expenditures, need not apply to local expenditures. The plan of the discussion is first to restate the assumptions made by Musgrave and Samuelson and the central problems with which they deal. After looking at a key difference between the federal versus local cases, I shall present a simple model. This model yields a solution for the level of expenditures for local public goods which reflects the preferences of the population more adequately than they can be reflected at the national level. The assumptions of the model will then be relaxed to see what implications are involved. Finally, policy considerations will be discussed.
12,105 citations
TL;DR: This chapter discusses the application of the diagonal process of the universal computing machine, which automates the calculation of circle and circle-free numbers.
Abstract: 1. Computing machines. 2. Definitions. Automatic machines. Computing machines. Circle and circle-free numbers. Computable sequences and numbers. 3. Examples of computing machines. 4. Abbreviated tables Further examples. 5. Enumeration of computable sequences. 6. The universal computing machine. 7. Detailed description of the universal machine. 8. Application of the diagonal process. Pagina 1 di 38 On computable numbers, with an application to the Entscheidungsproblem A. M. ...
7,642 citations
Book•
[...]
01 Jan 1917
TL;DR: This book is an application of some of the concepts of physical science and sundry mathematical methods to the study of organic form and is like one of Darwin's books, well-considered, patiently wrought-out, learned, and cautious.
Abstract: Introduction John Tyler Bonner VII 1. Introductory 2. On magnitude 3. The forms of cells 4. The forms of tissues, of cell-aggregates 5. On spicules and spicular skeletons 6. The equiangular spiral 7. The shapes of horns and of teeth or tusks 8. On form and mechanical efficiency 9. On the theory of transformations, or the comparison of related forms 10. Epilogue Index.
4,470 citations
Book•
01 Jan 1976
TL;DR: Hirsch and Mathews as discussed by the authors describe the true story of Ulam's pivotal role in the making of the "Super," in their historical introduction to this behind-the-scenes look at the minds and ideas that ushered in the nuclear age.
Abstract: This autobiography of mathematician Stanislaw Ulam, one of the great scientific minds of the twentieth century, tells a story rich with amazingly prophetic speculations and peppered with lively anecdotes. As a member of the Los Alamos National Laboratory from 1944 on, Ulam helped to precipitate some of the most dramatic changes of the postwar world. He was among the first to use and advocate computers for scientific research, originated ideas for the nuclear propulsion of space vehicles, and made fundamental contributions to many of today's most challenging mathematical projects. With his wide-ranging interests, Ulam never emphasized the importance of his contributions to the research that resulted in the hydrogen bomb. Now Daniel Hirsch and William Mathews reveal the true story of Ulam's pivotal role in the making of the 'Super,' in their historical introduction to this behind-the-scenes look at the minds and ideas that ushered in the nuclear age. It includes an epilogue by Francoise Ulam and Jan Mycielski that sheds new light on Ulam's character and mathematical originality.
493 citations
TL;DR: In this article, the El Farol problem is modeled as a game, and the set of Nash equilibria in mixed strategies of this game is analyzed analytically, showing that the method of inductive inference employed by the agents in Arthur's computer simulation leads the empirical distribution of aggregate attendance to be like those in the Nash equilibrium of the game.
Abstract: In this paper I study the El Farol problem, a deterministic, boundedly rational, multi-agent model of a resource subject to congestion externalities that was initially studied computationally by Arthur (1994). I represent the interaction as a game, compute the set of Nash equilibria in mixed strategies of this game, and show analytically how the method of inductive inference employed by the agents in Arthur's computer simulation leads the empirical distribution of aggregate attendance to be like those in the set of Nash equilibria of the game. This set contains only completely mixed strategy profiles, which explains why aggregate attendance appears random in the computer simulation even though its set-up is completely deterministic.
28 citations