The Effect of Bidding Information in Ascending Auctions.

We study the effect of the drop out and reenter information in an environment where bidders' values involve both private and common value components. We find that (1) providing bidding information does not have a significant effect on expected revenue and expected efficiency. (2) The effect of information on winner's expected profit depends on the range of uncertainty of the common value component and the level of Nash profit prediction, which the auctioneer has no a priori knowledge. In our environment, where bidders have a private component to their value and the auction takes place in ascending clock format, (3) bidders do not suffer from the winner's curse when information is not provided. (4) Information substantially increases the variability of revenue and winner?s profit when the range of uncertainty of the common value component is large. (5) Bidders? response to information depends on the range of uncertainty.

Analyzing P300 Distractors for Target Reconstruction

P300-based brain-computer interfaces (BCIs) are often trained per-user and per-application space. Training such models requires ground truth knowledge of target and non-target stimulus categories during model training, which imparts bias into the model. Additionally, not all non-targets are created equal; some may contain visual features that resemble targets or may otherwise be visually salient. Current research has indicated that non-target distractors may elicit attenuated P300 responses based on the perceptual similarity of these distractors to the target category. To minimize this bias, and enable a more nuanced analysis, we use a generalized BCI approach that is fit to neither user nor task. We do not seek to improve the overall accuracy of the BCI with our generalized approach; we instead demonstrate the utility of our approach for identifying target-related image features. When combined with other intelligent agents, such as computer vision systems, the performance of the generalized model equals that of the user-specific models, without any user specific data.Comment: 4 pages, 3 figure

EEG-Based User Reaction Time Estimation Using Riemannian Geometry Features

Riemannian geometry has been successfully used in many brain-computer interface (BCI) classification problems and demonstrated superior performance. In this paper, for the first time, it is applied to BCI regression problems, an important category of BCI applications. More specifically, we propose a new feature extraction approach for Electroencephalogram (EEG) based BCI regression problems: a spatial filter is first used to increase the signal quality of the EEG trials and also to reduce the dimensionality of the covariance matrices, and then Riemannian tangent space features are extracted. We validate the performance of the proposed approach in reaction time estimation from EEG signals measured in a large-scale sustained-attention psychomotor vigilance task, and show that compared with the traditional powerband features, the tangent space features can reduce the root mean square estimation error by 4.30-8.30%, and increase the estimation correlation coefficient by 6.59-11.13%.Comment: arXiv admin note: text overlap with arXiv:1702.0291

MECHANISMS FOR ADDRESSING THIRD-PARTY IMPACTS RESULTING FROM VOLUNTARY WATER TRANSFERS

This research uses laboratory experiments to test alternative water market institutions designed to protect third-party interests. The institutions tested include taxing mechanisms that raise revenue to compensate affected third-parties, and a free market in which third-parties actively participate. We also discuss the likely implications of a command-and-control approach in which there are fixed limits on the volume of water that may be exported from a region. The results indicate that there are some important trade-offs in selecting a policy option. Although theoretically optimal, active third-party participation in the market is likely to result in free-riding that may erode some or all of the efficiency gains, and may introduce volatility into the market. Fixed limits on water exports are likely to result in a more stable market, but the constraints on exports will result in lower levels of social welfare. Taxing transfers and compensating third-parties offers a promising balance of efficiency, equity and market stability.Resource /Energy Economics and Policy,

An Experimental Examination of the Walrasian Tatonnement Mechanism

Joyce (1984) reports results of experiments of a Walrasian tatonnement auction that show that the mechanism is stable, exhibits strong convergence properties and generates efficiency averaging better than 97%. He also found that when subjects could see part of the order flow (excess demand), price tended to be lower (favorable to buyers). His experiments consisted of a stationary environment where subjects were provided with single-unit supply and demand functions. This paper assesses the robustness of his results in a more complex setting and systematically investigates the effect of various order flow information and message restriction rules on the performance of the Walrasian mechanism. In particular, our subjects were provided with multi-unit demands and supplies where equilibrium price and subject values or costs were changed each trading period

Computed Tomography in Trauma Patients Accepted in Transfer:: Missed Injuries and Rationale for Repeat Imaging. Can we do Better?

Introduction. Computed tomography scans often are repeated ontrauma patient transfers, leading to increased radiation exposure,resource utilization, and costs. This study examined the incidenceof repeated computed tomography scans (RCT) in trauma patienttransfers before and after software upgrades, physician education,and encouragement to reduce RCT.Methods.xThe number of RCTs at an American College of SurgeonsCommittee on Trauma verified level 1 trauma center was measured.The trauma team was educated and encouraged to use the computedtomography scans received with transfer trauma patients as perstudy protocol. All available images were reviewed and reasons for aRCT when ordered were recorded and categorized. Impact of systemimprovements and education on subsequent RCT were evaluated.Results. A RCT was done on 47.2% (n = 76) of patients throughoutthe study period. Unacceptable image quality and possible misseddiagnoses were the most commonly reported reasons for a RCT. Preventablereasons for a RCT (attending refusal to read outside films,incompatible software, and physician preference) decreased from25.8 to 14.3% over the study periods.Conclusions. The volume of unnecessary RCT can be reduced primarilythrough software updates and physician education, therebydecreasing radiation exposure, patient cost, and inefficiencies in hospitalresource usage. Kans J Med 2019;12(1):7-10

Brane World Cosmology Without the Z_2 Symmetry

The Friedmann equation for a positive tension brane situated between two bulk spacetimes that posses the same 5D cosmological constant, but which does not posses a Z2 symmetry of the metric itself is derived, and the possible effects of dropping the Z2 symmetry on the expansion of our Universe are examined; cosmological constraints are discussed. We show the effect of this is an inflation-like period at very early times. The global solutions for the metric in the infinite extra dimension case are found and comparison with the symmetric case is made. We show that any brane world senario of this type must revert to a Z2 symmetric form at late times, and hence rule out certain proposed scenarios