Design of Resilient Sensor Networks Balancing Resilience and Efficiency

In recent years,the notion of resilience has been developed and applied in many technical areas,becoming exceptionally pertinent to disaster risk science.During a disaster situation,accurate sensing information is the key to efficient recovery efforts.In general,resilience aims to minimize the impact of disruptions to systems through the fast recovery of critical functionality,but resilient design may require redundancy and could increase costs.In this article,we describe a method based on binary linear programming for sensor network design balancing efficiency with resilience.The application of the developed framework is demonstrated for the case of interior building surveillance utilizing infrared sensors in both twoand three-dimensional spaces.The method provides optimal sensor placement,taking into account critical functionality and a desired level of resilience and considering sensor type and availability.The problem formulation,resilience requirements,and application of the optimization algorithm are described in detail.Analysis of sensor locations with and without resilience requirements shows that resilient configuration requires redundancy in number of sensors and their intelligent placement.Both tasks are successfully solved by the described method,which can be applied to strengthen the resilience of sensor networks by design.The proposed methodology is suitable for large-scale optimization problems with many sensors and extensive coverage areas.

Shorebird patches as fingerprints of fractal coastline fluctuations due to climate change

Introduction:The Florida coast is one of the most species-rich ecosystems in the world.This paper focuses on the sensitivity of the habitat of threatened and endangered shorebirds to sea level rise induced by climate change,and on the relationship of the habitat with the coastline evolution.We consider the resident Snowy Plover(Charadrius alexandrinus nivosus),and the migrant Piping Plover(Charadriusmelodus)and Red Knot(Calidris canutus)along the Gulf Coast of Mexico in Florida.Methods:We analyze and model the coupled dynamics of habitat patches of these imperiled shorebirds and of the shoreline geomorphology dictated by land cover change with consideration of the coastal wetlands.The land cover is modeled from 2006 to 2100 as a function of the A1B sea level rise scenario rescaled to 2 m.Using a maximum-entropy habitat suitability model and a set of macroecological criteria we delineate breeding and wintering patches for each year simulated.Results:Evidence of coupled ecogeomorphological dynamics was found by considering the fractal dimension of shorebird occurrence patterns and of the coastline.A scaling relationship between the fractal dimensions of the species patches and of the coastline was detected.The predicted power law of the patch size emerged from scale-free habitat patterns and was validated against 9 years of observations.We predict an overall 16%loss of the coastal landforms from inundation.Despite the changes in the coastline that cause habitat loss,fragmentation,and variations of patch connectivity,shorebirds self-organize by preserving a power-law distribution of the patch size in time.Yet,the probability of finding large patches is predicted to be smaller in 2100 than in 2006.The Piping Plover showed the highest fluctuation in the patch fractal dimension;thus,it is the species at greatest risk of decline.Conclusions:We propose a parsimonious modeling framework to capture macroscale ecogeomorphological patterns of coastal ecosystems.Our results suggest the potential use of the fractal dimension of a coastline as a fingerprint of climatic change effects on shoreline-dependent species.Thus,the fractal dimension is a potential metric to aid decision-makers in conservation interventions of species subjected to sea level rise or other anthropic stressors that affect their coastline habitat.

Business Continuity Management,Operational Resilience,and Organizational Resilience:Commonalities,Distinctions,and Synthesis

The concepts of business continuity management,operational resilience,and organizational resilience each refer to actions that businesses and organizations can take in anticipating and responding to disruptions.However,the existing definitions and usages are difficult to differentiate due to overlapping objectives,implementation processes,and outcomes.This article examines definitions and approaches for these three concepts and suggest a framework to operationalize methods and tools relevant to each.These definitions emphasize three dyads:risk versus resilience;organizational processes versus assets;and normal operating conditions versus crisis conditions.Using these dyads to differentiate the concepts of business continuity management,operational resilience,and organizational resilience can support planners in clarifying objectives and identifying which approach will be most beneficial as businesses or organizations plan for and encounter disruptions.This article evaluates these concepts by examining illustrative examples of disruptions and responses.