Placing dynamic sensors and actuators on flexible space structures

Input/Output Cost Analysis involves decompositions of the quadratic cost function into contributions from each stochastic input and each weighted output. In the past, these suboptimal cost decomposition methods of sensor and actuator selection (SAS) have been used to locate perfect (infinite bandwidth) sensor and actuators on large scale systems. This paper extends these ideas to the more practical case of imperfect actuators and sensors with dynamics of their own. NASA's SCOLE examples demonstrate that sensor and actuator dynamics affect the optimal selection and placement of sensors and actuators

Complex genome evolution in Anopheles coluzzii associated with increased insecticide usage in Mali.

In certain cases, a species may have access to important genetic variation present in a related species via adaptive introgression. These novel alleles may interact with their new genetic background, resulting in unexpected phenotypes. In this study, we describe a selective sweep on standing variation on the X chromosome in the mosquito Anopheles coluzzii, a principal malaria vector in West Africa. This event may have been influenced by the recent adaptive introgression of the insecticide resistance gene known as kdr from the sister species Anopheles gambiae. Individuals carrying both kdr and a nearly fixed X-linked haplotype, encompassing at least four genes including the P450 gene CYP9K1 and the cuticular protein CPR125, have rapidly increased in relative frequency. In parallel, a reproductively isolated insecticide-susceptible A. gambiae population (Bamako form) has been driven to local extinction, likely due to strong selection from increased insecticide-treated bed net usage

Social Sustainability in Trade and Development Policy: A Life Cycle Approach to Understanding and Managing Social Risk Attributable to Production and Consumption in the EU-27

Improving social sustainability within Europe and abroad is among the founding premises of the European Union. European Commission external policy documents – in particular, those associated with trade and development - explicitly call for the use of policy instruments as a means of improving social conditions in third countries. Unclear, however, is the extent to which progress in social sustainability as a result of Commission policy measures is being assessed, or measures to further leverage improved social sustainability implemented. Life cycle thinking (LCT) refers to a management philosophy predicated on holistic consideration of management alternatives for the purpose of preventing unintentional burden shifting – whether between supply chain activities or issue areas. Significant strides have already been made in the environmental domain to operationalize life cycle thinking in European Commission policies, with supporting methodological norms, frameworks, tools and data. To date, comparable approaches and instruments are lacking in support of life cycle-based social sustainability policy initiatives. Such information and tools are critical in support of improved policy design, implementation, monitoring and/or reformulation. Social risk refers to the potential for one or more parties to be exposed to negative social conditions that, in turn, undermine social sustainability. We conducted a macro-scale analysis of the social risk profile of EU-27 trade by combining trade statistics regarding imports from intra- and extra-territorial trading partners in 2010 with country and sector-specific social risk indicator data. These data cover 17 social themes in five thematic areas: Labour Rights and Decent Work; Health and Safety; Human Rights; Governance; and Community Infrastructure. We assessed the apparent social risk profiles of EU-27 imports based on consideration of country-of-origin social risk data only, compared to a life cycle-based social risk assessment which took into account the distribution of social risk along product supply chains. Our intention was to better understand how and to what extent current trade-based consumption in the EU-27 may be associated with socially unsustainable conditions, and the value of applying a life cycle perspective for sustainability management in this context. Our analysis underscores the importance of a life cycle-based approach to understanding and managing social risk in support of policies for socially sustainable development. Moreover, the methods and information presented herein offer a potentially powerful decision-support tool for policy makers wishing to better understand the magnitude and distribution of social risk associated with EU production and consumption patterns, the mitigation of which will contribute to socially sustainable development within Europe and abroad. A novel opportunity hence presents itself for decision makers and those who provide scientific and technical support to policy making to collaborate closely in moving forward the agenda for socially sustainable development. This will require the identification of strategic policy directions and supporting research projects, building upon existing, complementary environmental and economic sustainability assessment tools within the European Commission, which will continue to strengthen the elaboration, implementation, and impact assessment of science-based policy for sustainable development.JRC.H.8 - Sustainability Assessmen

Simulation of Hazards and Poses for a Rocker-Bogie Rover

Provisions for specification of hazards faced by a robotic vehicle (rover) equipped with a rocker-bogie suspension, for prediction of collisions between the vehicle and the hazards, and for simulation of poses of the vehicle at selected positions on the terrain have been incorporated into software that simulates the movements of the vehicle on planned paths across the terrain. The software in question is that of the Web Interface for Telescience (WITS), selected aspects of which have been described in a number of prior NASA Tech Briefs articles. To recapitulate: The WITS is a system of computer software that enables scientists, located at geographically dispersed computer terminals connected to the World Wide Web, to command instrumented robotic vehicles (rovers) during exploration of Mars and perhaps eventually of other planets. The WITS also has potential for adaptation to terrestrial use in telerobotics and other applications that involve computer-based remote monitoring, supervision, control, and planning

Form factor for a family of quantum graphs: An expansion to third order

For certain types of quantum graphs we show that the random-matrix form factor can be recovered to at least third order in the scaled time $\tau$ from periodic-orbit theory. We consider the contributions from pairs of periodic orbits represented by diagrams with up to two self-intersections connected by up to four arcs and explain why all other diagrams are expected to give higher-order corrections only. For a large family of graphs with ergodic classical dynamics the diagrams that exist in the absence of time-reversal symmetry sum to zero. The mechanism for this cancellation is rather general which suggests that it may also apply at higher-orders in the expansion. This expectation is in full agreement with the fact that in this case the linear-$\tau$ contribution, the diagonal approximation, already reproduces the random-matrix form factor for $\tau<1$. For systems with time-reversal symmetry there are more diagrams which contribute at third order. We sum these contributions for quantum graphs with uniformly hyperbolic dynamics, obtaining $+2\tau^{3}$, in agreement with random-matrix theory. As in the previous calculation of the leading-order correction to the diagonal approximation we find that the third order contribution can be attributed to exceptional orbits representing the intersection of diagram classes.Comment: 23 pages (including 4 fig.) - numerous typos correcte

Skyline Sketches: The Yellow Lily

A boy picks a yellow pond lily and regrets it

Energy conservation potential uncertainty analysis

Previous studies which have generated estimates of the potential for cost-effective gains in energy efficiency have generally acknowledged the uncertainty in their inputs and conclusions, but none have gone beyond simple scenario analysis to quantify the uncertainties in their inputs or conclusions. This research develops and demonstrates methods for the explicit treatment of uncertainty in energy conservation potential analysis. New methods and critical data requirements are highlighted through application to the study of current weatherization potential. Sensitivity analysis finds that, contrary to claims appearing in the literature, estimates of cost-effective conservation potential are more sensitive to uncertainties in empirical inputs than to variations in assumed discount rates. A taxonomy of the input uncertainties affecting estimates of current weatherization potential is developed. The availability of data to support estimates of each input uncertainty is found to be minimal. Estimates of annual energy savings are the most uncertain input to the analysis of current weatherization potential. This input\u27s uncertainty is also significantly more complex to analyze and characterize than that of either installed cost or measure lifetime (for weatherization measures), because of the number of separate factors contributing to it. Methods are demonstrated for translating probabilistic descriptions of input uncertainties into probabilistic measure-specific conclusions. Methods for aggregating and plotting these results in modified conservation supply curves are presented. Ninety percent confidence intervals for population mean cost of conserved energy per weatherization measure are estimated to range from roughly 60% to nearly 400% of typical point estimates. Ninety percent confidence intervals for population mean annual energy savings per weatherization measure are estimated to be less wide but still significant, ranging from roughly 35% to 160% of typical point estimates. The most significant contributor to uncertainty in both of these outputs is uncertainty in estimates of annual energy savings per measure installation. Probabilistic conclusions about the supply curve as a whole, as well as confidence intervals for such summary results as the total technical potential and the total cost-effective conservation potential given a threshold price, all require specification of the statistical dependence of each uncertainty\u27s influence upon separate measures

Quantifying the Detrimental Impacts of Land-Use and Management Change on European Forest Bird Populations

The ecological impacts of changing forest management practices in Europe are poorly understood despite European forests being highly managed. Furthermore, the effects of potential drivers of forest biodiversity decline are rarely considered in concert, thus limiting effective conservation or sustainable forest management. We present a trait-based framework that we use to assess the detrimental impact of multiple land-use and management changes in forests on bird populations across Europe. Major changes to forest habitats occurring in recent decades, and their impact on resource availability for birds were identified. Risk associated with these changes for 52 species of forest birds, defined as the proportion of each species' key resources detrimentally affected through changes in abundance and/or availability, was quantified and compared to their pan-European population growth rates between 1980 and 2009. Relationships between risk and population growth were found to be significantly negative, indicating that resource loss in European forests is an important driver of decline for both resident and migrant birds. Our results demonstrate that coarse quantification of resource use and ecological change can be valuable in understanding causes of biodiversity decline, and thus in informing conservation strategy and policy. Such an approach has good potential to be extended for predictive use in assessing the impact of possible future changes to forest management and to develop more precise indicators of forest health