Complex Systems Task Group Summaries (2009) / Chapter Skim
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Task Group Summary 9--Can one control flow and transport in complex systems?
Task Group Summary 9--Can one control flow and transport in complex systems?
Pages 73-84
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From page 73... ...
The nature of this transport depends both on the properties of the individual components and on the overall geometrical and topological structure of the system. In simple physical systems, we typically find either "ballistic" transport -- that is, the distance travelled is proportional to time, as in the flight of a projectile -- or "diffusive" transport -- that is, the distance traveled is proportional to the square-root of time, as in Brownian motion describing the spread of a drop of dye in an unstirred liquid.
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From page 74... ...
Our attempt to understand the nature of transport in complex systems is in large part driven by the goal of controlling this transport. In some cases, we want to enhance transport: for instance, increasing the ability of the Internet to carry messages, enhancing traffic flow, increasing the rate of oil recovery or the efficiency of mixing and disseminating information in the case of a crisis, etc.
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From page 75... ...
In the aftermath of the human genome sequencing project, systems biologists are developing concepts, tools, and resources to model interactome networks with the goal of modeling differences of systems properties between cancerous and non-cancerous cellular networks. The ultimate goal of this endeavor is the design of drugs that would be able to alter systems properties of cancer cells to either kill them specifically or dramatically slow their malignant progression.
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From page 76... ...
First, the rapid spread of computer viruses with pandemic consequences is enabled by the Internet: can we develop a means of identifying these viruses as they travel and prevent them from attacking individual computers (i.e., severing the links)
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From page 77... ...
Proc Natl Acad Sci USA 2004;101:15124-15129. Severe Acute Respiratory Syndrome (SARS)
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From page 78... ...
Kumar, Louisiana State University • Ying-Cheng-Lai, Arizona State University • Shayan Mookherjea, University of California San Diego • Frederick Moxley II, United States Military Academy • Michael J North, Argonne National Laboratory • Juan Ocampo, Trajectory Asset Management • Iraj Saniee, Bell Laboratories, Alcatel-Lucent • Alessandro Vespignani, Indiana University • Anne-Marie Corley, MIT TASK GROUP SUMMARY – GROUP A By Anne-Marie Corley, Graduate Science Writing Student, MIT A group of scientists, representing many disciplines at the 2008 National Academies Keck Futures Initiative Conference in Irvine, California, was asked to consider this question: Can one control flow and transport in a complex system?
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From page 79... ...
After considering a range of ideas such as detecting the next zoonotic disease to hop from animals to humans, locating networks of terrorists interacting in space and time, or controlling transportation flow to inhibit the spread of epidemics, the group decided to focus on two example application areas -- namely the financial system's credit flow and the role of commuting patterns in the spread of epidemics. The group placed primary emphasis on the financial system's credit flow and used the spread of epidemics example as a check for logical clarity.
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From page 80... ...
number of web browser read accesses of official informational web sites, (2) patterns of search engine queries (e.g., Google searches)
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From page 81... ...
TASK GROUP MEMBERS – GROUP B • Lajos Balogh, Roswell Park Cancer Institute • Peter Cummings, Vanderbilt University • Martin Gruebele, University of Illinois • Rigoberto Hernandez, Georgia Institute of Technology • Maia Martcheva, University of Florida • Saira Mian, Lawrence Berkeley National Laboratory • Peter Sloot, University of Amsterdam • Jeffrey Toretsky, Georgetown University • Muhammad Zaman, University of Texas at Austin • Brian Creech, University of Georgia TASK GROUP SUMMARY – GROUP B By Brian Creech, Graduate Science Writing Student, University of Georgia Charged with the problem of how to control transport in complex systems, a group of scientists at the 2008 National Academies Keck Futures Initiative Conference on Complex Systems agreed that a control mechanism should be simple, impacting transport while also presenting the fewest negative effects on the health of that system. In Task Group (9B)
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From page 82... ...
The human HIV/AIDS pandemic was viewed as a disease transported across a network where nodes correspond to individuals; cities are a series of dynamic nodes connected by airlines, with the disease being transported via the changing social/sexual connections among infected and non-infected individuals within the cities. Metastatic cancer was modeled as a network within the human body that uses the lymphatic system and the venous system to transport cancer from one organ to the next. The body's organs are themselves dynamic networks, and are subject to the same characteristics of a larger dynamic network. Both examples have important similarities, but their differences impact how diseases move across the networks.
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From page 83... ...
This model looks at metastases -- the spread of cancer cells to new parts of the body, for example malignant breast cancer cells moving to the bones -- as a structural phenomenon. The body's immune system offers a means of implementing control.
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From page 84... ...
Endoscopic imaging techniques have been used to observe cancer cells in the gastrointestinal tract and may provide the necessary means of tracking the mechanism for metastatic spread. Conclusions The unique features of individual networks affect the patterns of flow within that network.
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