210 research outputs found

    Robust decision analysis for environmental management of groundwater contamination sites

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    In contrast to many other engineering fields, the uncertainties in subsurface processes (e.g., fluid flow and contaminant transport in aquifers) and their parameters are notoriously difficult to observe, measure, and characterize. This causes severe uncertainties that need to be addressed in any decision analysis related to optimal management and remediation of groundwater contamination sites. Furthermore, decision analyses typically rely heavily on complex data analyses and/or model predictions, which are often poorly constrained as well. Recently, we have developed a model-driven decision-support framework (called MADS; http://mads.lanl.gov) for the management and remediation of subsurface contamination sites in which severe uncertainties and complex physics-based models are coupled to perform scientifically defensible decision analyses. The decision analyses are based on Information Gap Decision Theory (IGDT). We demonstrate the MADS capabilities by solving a decision problem related to optimal monitoring network design.Comment: This paper has been withdrawn by the author due to a crucial sign error in equations 7 and

    Uncertainties in the Transient Capture-Zone Estimates of Groundwater Supply Wells

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    Capture zones of water-supply wells are a widely used analysis tool for protection of groundwater resources. Transient analyses of capture zones provide a more complete assessment than the commonly applied steady-state analyses. Previously, we have demonstrated that advection-only analyses can produce biased transient capture-zone estimates. Therefore, it is important to consider the dispersion of contaminant plumes. Here, we extend our study to incorporate temporal and spatial distribution in the contaminant sources and their respective uncertainties. Our analysis indicates that the capture-zone estimates can be very sensitive to the transients in the contaminant releases. Even relatively small uncertainties in the contaminant source, when combined with transient flow effects associated with natural variability of gradients or water-supply pumping, can cause significant uncertainties in the capture-zone estimates. This conclusion has important practical implications. Furthermore, we investigate the impact of uncertainty in the longitudinal and transverse dispersivities on the transient capture estimates

    Research on Option Trading Strategies

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    Options are one of the most used financial instruments nowadays. The goal of the project is to analyze different options trading strategies. The research includes ways to price and value options and creating delta hedging simulation, based on the Black/Scholes pricing model and Monte Carlo simulations

    Rediscovery of Asparagus stipularis Forskal (Family : Asparagaceae) in the Maltese Islands (Central Mediterranean)

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    The presence of A. stipularis on the island of Gozo (Maltese islands) is reported and information on distribution and habitat is given. Old unconfirmed records from the island of Malta are discussed.peer-reviewe

    FOFX Batch Performance Monitoring, Analytics, Ticket Management Metrics

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    The goal of the project is to produce metrics and analysis of the overnight batch processes at Lehman Brothers. Due to recent market forces and business initiatives there is a marked increase in trading volumes. Our task was to produce tools, which can help analyze, visualize and interpret the run time data, volume information and the delivery expectations, based on different statistic techniques. Another target of the project is to provide metrics and monitoring capability for the ticket management system at Lehman Brothers and to produce analysis for simple presentation of the ticket data in a variety of forms

    Nonnegative/binary matrix factorization with a D-Wave quantum annealer

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    D-Wave quantum annealers represent a novel computational architecture and have attracted significant interest, but have been used for few real-world computations. Machine learning has been identified as an area where quantum annealing may be useful. Here, we show that the D-Wave 2X can be effectively used as part of an unsupervised machine learning method. This method can be used to analyze large datasets. The D-Wave only limits the number of features that can be extracted from the dataset. We apply this method to learn the features from a set of facial images
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