In a paper published in the journal last month, authors Anthony Bonato, Dieter Mitsche, and Pawel Pralat describe a mathematical model to disrupt flow of information in a complex real-world network, such as a terrorist organization, using minimal resources.
Terror networks are comparable in their structure to hierarchical organization in companies and certain online social networks, where information flows in one direction from a source, which produces the information or data, downwards to sinks, which consume it. Such networks are called hierarchical social networks. Read the rest of this entry »
In a paper published last month in the SIAM/ASA Journal on Uncertainty Quantification, the father-son team of Jerome and Seth Stein describe a model that estimates the balance between costs and benefits of mitigation—efforts to reduce losses by taking action now to reduce consequences later— following natural disasters, as well as rebuilding defenses in their aftermath. Using the 2011 Tohoku earthquake in Japan as an example, the authors help answer questions regarding the kinds of strategies to employ against such rare events. Read the rest of this entry »
Computational models of the human heart can be very useful in studying not just the basic mechanisms of heart function, but also to analyze the heart in a diseased state, and come up with methods for diagnosis and therapy.
Dr. Natalia Trayanova’s Computational Cardiology Lab at the Johns Hopkins University is doing just that—her group uses mathematical models to look at cardiac function and dysfunction, examining the mechanisms behind disorders such as cardiac arrhythmias and pump dysfunction.
In a plenary lecture at the SIAM Conference on Computational Science and Engineering in February, Dr. Trayanova described how her lab uses imaging data from clinics, such as MRIs and CT scans, to create heart models. Using detailed information from such images, the team geometrically constructs 3-D computer models by incorporating information about chemical and protein interactions as well as cardiac fiber orientation. Read the rest of this entry »
Philadelphia, PA—Mathematical models can be used to study the spread of technological innovations among individuals connected to each other by a network of peer-to-peer influences, such as in a physical community or neighborhood. One such model was introduced in a paper published yesterday in the SIAM Journal on Applied Dynamical Systems.
Authors N. J. McCullen, A. M. Rucklidge, C. S. E. Bale, T. J. Foxon, and W. F. Gale focus on one main application: The adoption of energy-efficient technologies in a population, and consequently, a means to control energy consumption. By using a network model for adoption of energy technologies and behaviors, the model helps evaluate the potential for using networks in a physical community to shape energy policy. Read the rest of this entry »
A physiological model for sap exudation in maple trees
Philadelphia, PA—For many of us, maple syrup is an essential part of breakfast—a staple accompaniment to pancakes and waffles—but rarely do we think about the complicated and little-understood physiological aspects of syrup production. Each spring, maple growers in temperate regions around the world collect sap from sugar maple trees, which is one of the first steps in producing this delicious condiment.
However, the mechanisms behind sap exudation—processes that trigger pressure differences causing sap to flow— in maple trees are a topic of much debate. In a paper published today in the SIAM Journal on Applied Mathematics, authors Maurizio Ceseri and John Stockie shed light on this subject by proposing a mathematical model for the essential physiological processes that drive sap flow. Read the rest of this entry »
Philadelphia, PA—Social groups in a population can lend important cues to law enforcement officials, consumer-based services and risk assessors. Social and geographical patterns that provide information about such communities or gangs have been a popular subject for mathematical modeling.
In a paper published last month in the SIAM Journal on Applied Mathematics, authors use police department records about individuals’ social and geographical information to determine gang memberships.
Data on social interactions is particularly hard to come by, but in combination with geographical data, it can determine locations of specific groups in the population, such as gangs. For instance, if an individual’s geographic location at a set of times is known, social interactions may be inferred by detecting people present at the same place at the same time. In this manner, hotspots at major gang locations can be determined. Read the rest of this entry »
Philadelphia, PA—Whether you’ve watched an elaborate weather forecast, made an online purchase, or received personalized news stories in your inbox in recent years, you’ve likely seen “big data” in action.
Big data is everywhere these days, be it personalized ad targeting, weather and climate modeling, or flu trend analysis to mention just a few.
Ever-increasing amounts of data are now available thanks to many modern realities: e-commerce and transaction-based information that has been stored over the years, data streaming in from growing social media activity and rising Web traffic, and sensor data from the increased use of digital sensors in industrial equipment, electrical meters, automobiles, and satellites, for example. With decreasing storage costs, archiving this data has also become easier than ever. Read the rest of this entry »
Philadelphia, PA—None of us want to experience events like the Camelford water pollution incident in Cornwall, England, in the late eighties, or more recently, the Crestwood, Illinois, water contamination episode in 2009 where accidental pollution of drinking water led to heart-wrenching consequences to consumers, including brain damage, high cancer risk, and even death. In the case of such catastrophes, it is important to have a method to identify and curtail contaminations immediately to minimize impact on the public.
A paper published earlier this month in the SIAM Journal on Applied Mathematics considers the identification of contaminants in a water distribution network as an optimal control problem within a networked system. Read the rest of this entry »
Philadelphia, PA—Scientists have estimated that there are 1.7 million species of animals, plants and algae on earth, and new species continue to be discovered. Unfortunately, as new species are found, many are also disappearing, contributing to a net decrease in biodiversity. The more diversity there is in a population, the longer the ecosystem can sustain itself. Hence, biodiversity is key to ecosystem resilience.
Disease, destruction of habitats, pollution, chemical and pesticide use, increased UV-B radiation, and even the presence of new species are some of the causes for disappearing species. “Allee effect,” the phenomenon by which a population’s growth declines at low densities, is another key reason for perishing populations, and is an overriding feature of a paper published last month in the SIAM Journal on Applied Mathematics. Read the rest of this entry »
Philadelphia, PA—Studying the dynamics of the ocean system can greatly improve our understanding of key processes of ocean circulations, which have implications for future climate. Can applying mathematics to the research help? Dr. Emily Shuckburgh of the British Antarctic Survey, speaking at the 2012 SIAM Annual Meeting, thinks the answer is an emphatic “yes.”
Dr. Shuckburgh described mathematical ideas from dynamical systems used by her group, along with numerical modeling and experimental observations, to analyze circulation in the Southern Ocean. The Southern Ocean is unique in that it connects three major ocean basins—the Pacific, the Atlantic and the Indian oceans—with a powerful current that circulates all the way around Antarctica. This circumpolar current travels from the North Atlantic, sinking down to the bottom of the ocean and coming up to the surface around Antarctica, thus connecting the deep ocean with the atmosphere above. When water from the deep ocean comes up to the surface, it can exchange heat and carbon dioxide from the atmosphere, thus making it highly significant for climate change. Read the rest of this entry »