Publications by authors named "Thomas Seager"

The concept of "resilience analytics" has recently been proposed as a means to leverage the promise of big data to improve the resilience of interdependent critical infrastructure systems and the communities supported by them. Given recent advances in machine learning and other data-driven analytic techniques, as well as the prevalence of high-profile natural and man-made disasters, the temptation to pursue resilience analytics without question is almost overwhelming. Indeed, we find big data analytics capable to support resilience to rare, situational surprises captured in analytic models.

View Article and Find Full Text PDF

It is now common practice in environmental life cycle assessment (LCA) to conduct sensitivity analyses to identify critical parameters and prioritize further research. Typical approaches include variation of input parameters one at a time to determine the corresponding variation in characterized midpoints or normalized and weighted end points. Generally, those input parameters that cause the greatest variations in output criteria are accepted as the most important subjects of further investigation.

View Article and Find Full Text PDF

Various emerging technologies challenge existing governance processes to identify, assess, and manage risk. Though the existing risk-based paradigm has been essential for assessment of many chemical, biological, radiological, and nuclear technologies, a complementary approach may be warranted for the early-stage assessment and management challenges of high uncertainty technologies ranging from nanotechnology to synthetic biology to artificial intelligence, among many others. This paper argues for a risk governance approach that integrates quantitative experimental information alongside qualitative expert insight to characterize and balance the risks, benefits, costs, and societal implications of emerging technologies.

View Article and Find Full Text PDF

Previous studies of multilayer network robustness model cascading failures via a node-to-node percolation process that assumes "strong" interdependence across layers-once a node in any layer fails, its neighbors in other layers fail immediately and completely with all links removed. This assumption is not true of real interdependent infrastructures that have emergency procedures to buffer against cascades. In this work, we consider a node-to-link failure propagation mechanism and establish "weak" interdependence across layers via a tolerance parameter α which quantifies the likelihood that a node survives when one of its interdependent neighbors fails.

View Article and Find Full Text PDF

Complex networked systems ranging from ecosystems and the climate to economic, social, and infrastructure systems can exhibit a tipping point (a "point of no return") at which a total collapse of the system occurs. To understand the dynamical mechanism of a tipping point and to predict its occurrence as a system parameter varies are of uttermost importance, tasks that are hindered by the often extremely high dimensionality of the underlying system. Using complex mutualistic networks in ecology as a prototype class of systems, we carry out a dimension reduction process to arrive at an effective 2D system with the two dynamical variables corresponding to the average pollinator and plant abundances.

View Article and Find Full Text PDF

Urban transportation systems are vulnerable to congestion, accidents, weather, special events, and other costly delays. Whereas typical policy responses prioritize reduction of delays under normal conditions to improve the efficiency of urban road systems, analytic support for investments that improve resilience (defined as system recovery from additional disruptions) is still scarce. In this effort, we represent paved roads as a transportation network by mapping intersections to nodes and road segments between the intersections to links.

View Article and Find Full Text PDF

Two analytic perspectives on environmental assessment dominate environmental policy and decision-making: risk analysis (RA) and life-cycle assessment (LCA). RA focuses on management of a toxicological hazard in a specific exposure scenario, while LCA seeks a holistic estimation of impacts of thousands of substances across multiple media, including non-toxicological and non-chemically deleterious effects. While recommendations to integrate the two approaches have remained a consistent feature of environmental scholarship for at least 15 years, the current perception is that progress is slow largely because of practical obstacles, such as a lack of data, rather than insurmountable theoretical difficulties.

View Article and Find Full Text PDF

Background: Decision analysis-a systematic approach to solving complex problems-offers tools and frameworks to support decision making that are increasingly being applied to environmental challenges. Alternatives analysis is a method used in regulation and product design to identify, compare, and evaluate the safety and viability of potential substitutes for hazardous chemicals.

Objectives: We assessed whether decision science may assist the alternatives analysis decision maker in comparing alternatives across a range of metrics.

View Article and Find Full Text PDF

We investigate the emergence of extreme events in interdependent networks. We introduce an inter-layer traffic resource competing mechanism to account for the limited capacity associated with distinct network layers. A striking finding is that, when the number of network layers and/or the overlap among the layers are increased, extreme events can emerge in a cascading manner on a global scale.

View Article and Find Full Text PDF

Current policies accelerating photovoltaics (PV) deployments are motivated by environmental goals, including reducing greenhouse gas (GHG) emissions by displacing electricity generated from fossil-fuels. Existing practice assesses environmental benefits on a net life-cycle basis, where displaced GHG emissions offset those generated during PV production. However, this approach does not consider that the environmental costs of GHG release during production are incurred early, while environmental benefits accrue later.

View Article and Find Full Text PDF

Current research policy and strategy documents recommend applying life cycle assessment (LCA) early in research and development (R&D) to guide emerging technologies toward decreased environmental burden. However, existing LCA practices are ill-suited to support these recommendations. Barriers related to data availability, rapid technology change, and isolation of environmental from technical research inhibit application of LCA to developing technologies.

View Article and Find Full Text PDF

Fundamental problems of environmental sustainability, including climate change and fisheries management, require collective action on a scale that transcends the political and cultural boundaries of the nation-state. Rational, self-interested neoclassical economic theories of human behavior predict tragedy in the absence of third party enforcement of agreements and practical difficulties that prevent privatization. Evolutionary biology offers a theory of cooperation, but more often than not in a context of discrimination against other groups.

View Article and Find Full Text PDF

The wicked problems that constitute sustainability require students to learn a different set of ethical skills than is ordinarily required by professional ethics. The focus for sustainability ethics must be redirected towards: (1) reasoning rather than rules, and (2) groups rather than individuals. This need for a different skill set presents several pedagogical challenges to traditional programs of ethics education that emphasize abstraction and reflection at the expense of experimentation and experience.

View Article and Find Full Text PDF

The emergence of nanotechnology has coincided with an increased recognition of the need for new approaches to understand and manage the impact of emerging technologies on the environment and human health. Important elements in these new approaches include life-cycle thinking, public participation and adaptive management of the risks associated with emerging technologies and new materials. However, there is a clear need to develop a framework for linking research on the risks associated with nanotechnology to the decision-making needs of manufacturers, regulators, consumers and other stakeholder groups.

View Article and Find Full Text PDF

The recent accident at the Fukushima I nuclear power plant in Japan (also known as Fukushima Daiichi) captured the world's attention and re-invigorated concerns about the safety of nuclear power technology. The Editors of Integrated Environmental Assessment and Management invited experts in the field to describe the primary issues associated with the control and release of radioactive materials to the environment, particularly those that are of importance to the health of the human populations and the ecological systems that populate our planet. This collection of invited short commentaries aims to inform on the safety of nuclear power plants damaged by natural disasters and provide a primer on the potential environmental impacts.

View Article and Find Full Text PDF

The implications of recent catastrophic disasters, including the Fukushima Daiichi nuclear power plant accident, reach well beyond the immediate, direct environmental and human health risks. In a complex coupled system, disruptions from natural disasters and man-made accidents can quickly propagate through a complex chain of networks to cause unpredictable failures in other economic or social networks and other parts of the world. Recent disasters have revealed the inadequacy of a classical risk management approach.

View Article and Find Full Text PDF

Emerging environmental threats such as novel chemical compounds, biological agents, and nanomaterials present serious challenges to traditional models of risk analysis and regulatory risk management processes. Even a massive expansion of risk and life-cycle assessment research efforts is unlikely to keep pace with rapid technological change resulting in new and modified materials with changing properties. Therefore, it is essential to have a framework for interpreting available information in the context of high uncertainty and a strategy for prioritizing research efforts to reduce those uncertainties that are most critical.

View Article and Find Full Text PDF

The recent investment boom and collapse of the corn ethanol industry calls into question the long-term sustainability of traditional approaches to biofuel technologies. Compared with petroleum-based transportation fuels, biofuel production systems are more closely connected to complex and variable natural systems. Especially as biofeedstock production itself becomes more independent of fossil fuel-based supports, stochasticity will become an increasingly important, inherent feature of biofuel feedstock production systems.

View Article and Find Full Text PDF

The unprecedented uncertainty associated with engineered nanomaterials greatly expands the need for research regarding their potential environmental consequences. However, decision-makers such as regulatory agencies, product developers, or other nanotechnology stakeholders may not find the results of such research directly informative of decisions intended to mitigate environmental risks. To help interpret research findings and prioritize new research needs, there is an acute need for structured decision-analytic aids that are operable in a context of extraordinary uncertainty.

View Article and Find Full Text PDF

Lignocellulosic biomass can be converted into ethanol through either biochemical or thermochemical conversion processes. Biochemical conversion involves hydrolysis and fermentation while thermochemical conversion involves gasification and catalytic synthesis. Even though these routes produce comparable amounts of ethanol and have similar energy efficiency at the plant level, little is known about their relative environmental performance from a life cycle perspective.

View Article and Find Full Text PDF

Life cycle impact assessment (LCIA) involves weighing trade-offs between multiple and incommensurate criteria. Current state-of-the-art LCIA tools typically compute an overall environmental score using a linear-weighted aggregation of characterized inventory data that has been normalized relative to total industry, regional, or national emissions. However, current normalization practices risk masking impacts that may be significant within the context of the decision, albeit small relative to the reference data (e.

View Article and Find Full Text PDF

An intensification of interest in environmental assessment during the last 2 decades has driven corporate efforts to better document environmental goals, improve environmental management systems, and increase awareness of the environmental and ecological effects of business operations. This trend has been motivated partly by regulatory requirements (such as the Toxics Release Inventory in the United States) and partly by the inclination of some large manufacturing firms to embrace a broader social and environmental mission characterized as "sustainability" or "ecoefficiency." Moreover, the importance of measurable objectives in the US government has been recognized at least since the Government Performance Results Act of 1993, which was intended to both improve the efficiency of government and the confidence of the American public in government managers.

View Article and Find Full Text PDF