2,970 research outputs found

    Issues in forest restoration: Carbon credits for restored western dry forests?

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    Paying for large-scale ecological restoration of dry forests on federally managed lands throughout the western United States is urgently needed, but also quite expensive. Most experts agree that federal dollars will not be enough to do the job. While one of the obvious ways to help pay for restoration of overstocked forests is from timber sale proceeds, there may be another option-the sale of carbon credits in the newly emerging carbon marketplace. In this white paper, we discuss the basic issues involved in carbon trading, especially as it applies to forests and forest restoration in the American West. While the current carbon market situation is unlikely to provide much economic advantage, emerging federal cap-and-trade legislation and continuing interest in "green" economics may soon support a market-based scenario where healthy, restored forests are valued for their prodigious ecosystem services

    GraphX: Unifying Data-Parallel and Graph-Parallel Analytics

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    From social networks to language modeling, the growing scale and importance of graph data has driven the development of numerous new graph-parallel systems (e.g., Pregel, GraphLab). By restricting the computation that can be expressed and introducing new techniques to partition and distribute the graph, these systems can efficiently execute iterative graph algorithms orders of magnitude faster than more general data-parallel systems. However, the same restrictions that enable the performance gains also make it difficult to express many of the important stages in a typical graph-analytics pipeline: constructing the graph, modifying its structure, or expressing computation that spans multiple graphs. As a consequence, existing graph analytics pipelines compose graph-parallel and data-parallel systems using external storage systems, leading to extensive data movement and complicated programming model. To address these challenges we introduce GraphX, a distributed graph computation framework that unifies graph-parallel and data-parallel computation. GraphX provides a small, core set of graph-parallel operators expressive enough to implement the Pregel and PowerGraph abstractions, yet simple enough to be cast in relational algebra. GraphX uses a collection of query optimization techniques such as automatic join rewrites to efficiently implement these graph-parallel operators. We evaluate GraphX on real-world graphs and workloads and demonstrate that GraphX achieves comparable performance as specialized graph computation systems, while outperforming them in end-to-end graph pipelines. Moreover, GraphX achieves a balance between expressiveness, performance, and ease of use

    Electrostatically Directed Visual Fluorescence Response of DNA-Functionalized Monolithic Hydrogels for Highly Sensitive Hg2+ Detection

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    This document is the Accepted Manuscript version of a Published Work that appeared in final form in Applied Materials and Interfaces, copyright © American Chemical Society after peer review and technical editing by publisher. To access the final edited and published work see http://dx.doi.org/10.1021/am101068cHydrogels are cross-linked hydrophilic polymer networks with low optical background and high loading capacity for immobilization of biomolecules. Importantly, the property of hydrogel can be precisely controlled by changing the monomer composition. This feature, however, has not been investigated in the rational design of hydrogel-based optical sensors. We herein explore electrostatic interactions between an immobilized mercury binding DNA, a DNA staining dye (SYBR Green I), and the hydrogel backbone. A thymine-rich DNA was covalently functionalized within monolithic hydrogels containing a positive, neutral, or negative backbone. These hydrogels can be used as sensors for mercury detection since the DNA can selectively bind Hg2+ between thymine bases inducing a hairpin structure. SYBR Green I can then bind to the hairpin to emit green fluorescence. For the neutral or negatively charged gels, addition of the dye in the absence of Hg2+ resulted in intense yellow background fluorescence, which was attributed to SYBR Green I binding to the unfolded DNA. We found that, by introducing 20% positively charged allylamine monomer, the background fluorescence was significantly reduced. This was attributed to the repulsion between positively charged SYBR Green I by the gel matrix as well as the strong binding between the DNA and the gel backbone. The signal-to-background ratio and detection limit was, respectively, improved by 6- and 9-fold using the cationic gel instead of neutral polyacrylamide gel. This study helps understand the electrostatic interaction within hydrogels, showing that hydrogels can not only serve as a high capacity matrix for sensor immobilization but also can actively influence the interaction between involved molecules.University of Waterloo || Natural Sciences and Engineering Research Council |

    TeD-SPAD: Temporal Distinctiveness for Self-supervised Privacy-preservation for video Anomaly Detection

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    Video anomaly detection (VAD) without human monitoring is a complex computer vision task that can have a positive impact on society if implemented successfully. While recent advances have made significant progress in solving this task, most existing approaches overlook a critical real-world concern: privacy. With the increasing popularity of artificial intelligence technologies, it becomes crucial to implement proper AI ethics into their development. Privacy leakage in VAD allows models to pick up and amplify unnecessary biases related to people's personal information, which may lead to undesirable decision making. In this paper, we propose TeD-SPAD, a privacy-aware video anomaly detection framework that destroys visual private information in a self-supervised manner. In particular, we propose the use of a temporally-distinct triplet loss to promote temporally discriminative features, which complements current weakly-supervised VAD methods. Using TeD-SPAD, we achieve a positive trade-off between privacy protection and utility anomaly detection performance on three popular weakly supervised VAD datasets: UCF-Crime, XD-Violence, and ShanghaiTech. Our proposed anonymization model reduces private attribute prediction by 32.25% while only reducing frame-level ROC AUC on the UCF-Crime anomaly detection dataset by 3.69%. Project Page: https://joefioresi718.github.io/TeD-SPAD_webpage/Comment: ICCV 202

    A Cold Gas Micro-Propulsion System for CubeSats

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    Potential civilian and government users have expressed a strong interest in CubeSat class satellites for military, scientific and commercial purposes. The U.S. Air Force Research Laboratories (AFRL), using DARPA funding, have contracted with The Aerospace Corporation in El Segundo, California to develop a CubeSat class spacecraft called the MEMS PicoSat Inspector (MEPSI). In turn, AFRL and Aerospace Corporation selected VACCO to provide a Micro-Propulsion System (MiPS) for MEPSI. This paper describes the resulting system design and its capabilities. Related micro-propulsion activities will also be reviewed including work with AeroAstro Inc. to develop an advanced MiPS using decomposing nitrous oxide as the propellant. The VACCO Micro-Propulsion System is an advanced subsystem based on our proprietary Chemically Etched Micro Systems (ChEMS) integrated fluidic circuit technology (patent #6,334,301). Extremely flexible and easily expanded, MiPS can be adapted to a wide range of small spacecraft. The current isobutane unit can deliver 34 Newton-seconds of total impulse with over 61,000 minimum impulse bit firings. MiPS brings true propulsion capabilities to micro-spacecraft for formation flying, attitude control and velocity change (delta-V). Reliability features such as all-welded titanium construction and redundant soft-seat microvalves compliment the simple selfpressurizing design. Instead of simply creating a miniature version of a conventional system, VACCO has taken a highly integrated system level approach that eliminates all tubing connections in favor of a single ChEMS manifold. When combined with our system-in-a-tank packaging design, the resulting propulsion system is a significant advancement over published alternatives. VACCO’s ChEMS Micro-Propulsion System is a titanium weldment about half the size of a VHS videocassette. Four ChEMS 55 mN Micro-Thrusters are located around the periphery of the module tilting 15o toward the mounting plane. A single axial 55 mN Micro-Thruster is located in the center of the XY plane. The axial Micro-Thruster nozzle doubles as a fill/vent port for the system. Two sets of connector pins protrude from the Tank through glass headers to retain pressure while making electrical connections to the host MEPSI spacecraft. One flight MiPS unit has been designed, built and tested at both VACCO and Aerospace Corporation. This paper will describe the MiPS in sufficient detail for potential users to perform a preliminary assessment against their requirements. Performance test data will be presented and conclusions drawn. Lessons learned and future development plans will also be delineated. VACCO will also outline a plan for making MiPS available for University CubeSat projects. The idea is to build a number of sets of MiPS parts less the core assembly. The core assembly controls all component interconnections and tangential thruster geometry. These critical features could be designed by the student team in order to customize MiPS for their purposes. By stocking the machined parts, lead times can be reduced to less than four months. In this way, students can gain valuable skills and experience while keeping the entire project to less than one-year in duration. In addition to providing a learning experience, students would benefit from the enhanced capability and flexibility propulsion would bring to their CubeSat design

    The Impact of Consumer Perceptions of Information Privacy and Security Risks on the Adoption of Residual RFID Technologies

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    In today’s global competitive environment, organizations face a variety of challenges. Continuous improvement in organizational efficiencies and improving the entire supply chain are necessary to stay competitive. Many organizations are adopting radio frequency identification technologies (RFID) as part of their information supply chains. These technologies provide many benefits to the organizations that use them. However, how these technologies affect the consumer and their willingness to adopt the technology is often overlooked. Many of these RFID tags remain active after the consumers purchase them. These RFID tags, placed in a product for one purpose and left in the product after the tags have served their purpose, are residual RFIDs. Residual RFID technology can have many positive and negative effects on consumers’ willingness to buy and use products containing RFID, and thus, on the business’s ability to sell products containing RFID. If consumers refuse to buy products with residual RFID tags in them, the business harm is greater than the business benefit, regardless of any gain in supply chain efficiency. In this study, we outline some of the advantages and disadvantages of Residual RFID from the consumer perspective, then follow up with an in depth survey and analysis of consumer perceptions. Using structural equation modeling (SEM) we demonstrate that consumers’ perceptions of privacy risk likelihood and privacy risk harm negatively impact their intentions to use this technology. The implications of these findings need to be considered before the pending implementation of residual RFID technologies in the supply chain on a mass scale
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