145 research outputs found

    Conjugate persuasion

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    We consider a class of persuasion games in which the sender has rank-dependent (Yaari (1987)) preferences. Like much of the recent Bayesian persuasion literature, we allow the sender to choose from a rich set of information structures and assume the receiver’s action depends only on her posterior expectation of a scalar state variable. Conjugate to the standard problem, our sender’s utility is linear in posterior the mean, but may be nonlinear in probabilities. We geometrically characterize the sender’s optimal commitment payoff and identify the corresponding optimal information structure. When the state is continuously distributed, communication takes a monotone partitional form. Our characterization admits a simple analysis of comparative statics—for instance, we find that “grading on a curve” is a feature of optimal design. Finally, we apply our analysis to several problems of economic interest including information design in auctions and elections, as well as the design of equilibrium insurance contracts in the face of the ‘favorite-longshot’ bias

    Conformal Invariance of (0,2) Sigma Models on Calabi-Yau Manifolds

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    Long ago, Nemeschansky and Sen demonstrated that the Ricci-flat metric on a Calabi-Yau manifold could be corrected, order by order in perturbation theory, to produce a conformally invariant (2,2) nonlinear sigma model. Here we extend this result to (0,2) sigma models for stable holomorphic vector bundles over Calabi-Yaus.Comment: 15 pages; references adde

    Book Reviews

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    Creating a Local History Archive at Your Public Library. Faye Phillips. Paper Cadavers: The Archives of Dictatorship in Guatemala. Kirsten Weld. The Silence of the Archives. David Thomas, Simon Fowler, and Valerie Johnson. The Bad-Ass Librarians of Timbuktu and Their Race to Save the World\u27s Most Precious Manuscripts. Joshua Hammer. The International Business Archives Handbook: Understanding and Managing the Historical Records of Business. Edited by Alison Turton. Putting Descriptive Standards to Work. Edited by Kris Kiesling and Christopher J. Prom. Moving Image and Sound Collections for Archivists. Anthony Cocciolo

    Maritime search and rescue in Nunavut, Canada : strengthening the system from the bottom up

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    Due to the impacts of climate change, maritime search and rescue requirements are increasing across Nunavut. The region’s vast size and cold climate combine to make time the enemy of all responders. The substantial distances involved in responding with Canadian Coast Guard (CCG) icebreakers or Royal Canadian Air Force aircraft based in the South mean that the arrival of federal resources on scene can take significant time. There are few vessels of opportunity in the region. Historically, however, there has been little sustained investment in community-based marine Search and Rescue (SAR) capabilities in the territory. This started to change in 2015 with the launch of the CCG’s Arctic SAR Project and, in 2018, with the creation of the Coast Guard’s new Arctic Region. This poster outlines the status of the community-based marine SAR system in Nunavut, assess efforts by the Coast Guard and its partners to strengthen the system, and suggest broadly applicable best practices

    Planetary Rover Simulation for Lunar Exploration Missions

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    When planning planetary rover missions it is useful to develop intuition and skills driving in, quite literally, alien environments before incurring the cost of reaching said locales. Simulators make it possible to operate in environments that have the physical characteristics of target locations without the expense and overhead of extensive physical tests. To that end, NASA Ames and Open Robotics collaborated on a Lunar rover driving simulator based on the open source Gazebo simulation platform and leveraging ROS (Robotic Operating System) components. The simulator was integrated with research and mission software for rover driving, system monitoring, and science instrument simulation to constitute an end-to-end Lunar mission simulation capability. Although we expect our simulator to be applicable to arbitrary Lunar regions, we designed to a reference mission of prospecting in polar regions. The harsh lighting and low illumination angles at the Lunar poles combine with the unique reflectance properties of Lunar regolith to present a challenging visual environment for both human and computer perception. Our simulator placed an emphasis on high fidelity visual simulation in order to produce synthetic imagery suitable for evaluating human rover drivers with navigation tasks, as well as providing test data for computer vision software development.In this paper, we describe the software used to construct the simulated Lunar environment and the components of the driving simulation. Our synthetic terrain generation software artificially increases the resolution of Lunar digital elevation maps by fractal synthesis and inserts craters and rocks based on Lunar size-frequency distribution models. We describe the necessary enhancements to import large scale, high resolution terrains into Gazebo, as well as our approach to modeling the visual environment of the Lunar surface. An overview of the mission software system is provided, along with how ROS was used to emulate flight software components that had not been developed yet. Finally, we discuss the effect of using the high-fidelity synthetic Lunar images for visual odometry. We also characterize the wheel slip model, and find some inconsistencies in the produced wheel slip behaviour

    Reproducibility of in-vivo OCT measured three-dimensional human lamina cribrosa microarchitecture

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    Purpose: To determine the reproducibility of automated segmentation of the three-dimensional (3D) lamina cribrosa (LC) microarchitecture scanned in-vivo using optical coherence tomography (OCT). Methods: Thirty-nine eyes (8 healthy, 19 glaucoma suspects and 12 glaucoma) from 49 subjects were scanned twice using swept-source (SS-) OCT in a 3.5x3.5x3.64 mm (400x400x896 pixels) volume centered on the optic nerve head, with the focus readjusted after each scan. The LC was automatically segmented and analyzed for microarchitectural parameters, including pore diameter, pore diameter standard deviation (SD), pore aspect ratio, pore area, beam thickness, beam thickness SD, and beam thickness to pore diameter ratio. Reproducibility of the parameters was assessed by computing the imprecision of the parameters between the scans. Results: The automated segmentation demonstrated excellent reproducibility. All LC microarchitecture parameters had an imprecision of less or equal to 4.2%. There was little variability in imprecision with respect to diagnostic category, although the method tends to show higher imprecision amongst healthy subjects. Conclusion: The proposed automated segmentation of the LC demonstrated high reproducibility for 3D LC parameters. This segmentation analysis tool will be useful for in-vivo studies of the LC. © 2014 Wang et al

    Digging Into Data White Paper:Trading Consequences

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    Scholars interested in nineteenth century global economic history face a voluminous historical record. Conventional approaches to primary source research on the economic and environmental implications of globalised commodity flows typically restrict researchers to specific locations or a small handful of commodities. By taking advantage of cutting edge computational tools, the project was able to address much larger data sets for historical research, and thereby provides historians with the means to develop new data driven research questions. In particular, this project has demonstrated that text mining techniques applied to tens of thousands of documents about nineteenth century commodity trading can yield a novel understanding of how economic forces connected distant places all over the globe and how efforts to generate wealth from natural resources impacted on local environments. The large scale findings that result from the application of these new methodologies would be barely feasible using conventional research methods. Moreover, the project vividly demonstrates how the digital humanities can benefit from transdisciplinary collaboration between humanists, computational linguists and information visualisation expertsPostprin
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