Boosting the Accuracy of Differentially-Private Histograms Through Consistency

We show that it is possible to significantly improve the accuracy of a general class of histogram queries while satisfying differential privacy. Our approach carefully chooses a set of queries to evaluate, and then exploits consistency constraints that should hold over the noisy output. In a post-processing phase, we compute the consistent input most likely to have produced the noisy output. The final output is differentially-private and consistent, but in addition, it is often much more accurate. We show, both theoretically and experimentally, that these techniques can be used for estimating the degree sequence of a graph very precisely, and for computing a histogram that can support arbitrary range queries accurately.Comment: 15 pages, 7 figures, minor revisions to previous versio

The Influence of Personality and Losses on Search in Decisions From Experience

Research in decision making has focused increasing attention on understanding search behavior without focusing on how individual differences might influence people’s search behavior. To increase our understanding of this topic, the present study examined how personality predicted the amount of search an individual engages in before making a risky decision. It was hypothesized that conscientiousness would be a positive predictor of search behavior and would emerge as an even stronger predictor of search behavior when choosing between options with negative outcomes. It was also hypothesized that neuroticism would be a negative predictor of search behavior and that individuals with higher levels of neuroticism would search even less before making a decision that involve losses. The analysis did not support either hypothesis with none of the personality measures being significant predictors of search behavior for either the gain or the loss condition. However, a significant difference was found between the correlation coefficients of neuroticism by decision domain with neuroticism being associated with people searching less in the loss domain when compared to the gain domain, although the correlations themselves were not significant. Suggestions for future research in understanding search behavior are provided to enhance our understanding of individual differences and decision making

The structural evolution of an ancient accretionary prism in the Damara Belt, Namibia

The Southern Marginal Zone (SMZ) of the Damara Belt, exposed in the Gaub Canyon in central Namibia, consists of fourteen lithotectonic units of high strain amphiholite facies rock with pelagic, hemi-pelagic and clastic sedimentary protoliths. These rocks are intercalated With lenses of metabasite. Regional high-pressure - low-temperature metamorphic conditions (~1O kbar and ~600°C) dominate the Southern and Southern Marginal Zones of the Damara Belt, leading to the interpretation that these tectonostratigraphic terranes formed in an accretionary prism along an ancient subduction margin. The structures in the SMZ are the result of progressive deformation, inferred to have initiated under low-grade metamorphic conditions (D₁) and evolved through prograde to peak metamorphism (D₂), ending in relatively low-temperature retrograde conditions (D₃). Each of the deformation phases is characterised by a foliation. D₁ is associated With pure shear dominated layer-parallel extension characterised by disrupted lithological layering and hedding-parallel foliation S₀+₁. D₃ is defined as deformation related to the formation of an axial-planar S₂ caused by folding of S₀+₁ around F₂ hinge lines. Widespread isoclinal recumbent folding resulted in transposition of these fahrics and the general foliation is thus termed S₀+₁+₂. This composite foliation contains a down-dip stretching lineation L₂. Folding was contemporaneous With top-to-the-SE directed thrusting in D₂ faults and shear zones that are seen to displace D₁ fabric. Fold hinge lines parallel to L₂ suggest D₂ is characterised by non-ideal simple shear. D₃ is defined by a crenulation cleavage S₃, at near right angles to S₀+₁+₂ foliation resulting from NW-SE pure shear shortening. This phase of deformation is also associated with retrograde, reverse faulting that is localised along some of the D₂ shear zones

Serial Investors and Early Stage Finance

This study examines the early stage investment activity of UK serial investors, individuals who have made at least three private investments. Two distinct groups emerged; one which invested on their own all the time ( solo serial investors ) and the other which invested with others almost exclusively ( syndicate serial investors ). Both groups had invested in a variety of industrial sectors, a majority of which were in sectors where no one in the investor group had previous direct experience. Concept familiarity appeared to be a necessary, albeit insufficient, prerequisite to the decision to invest. For a majority of the investments reviewed for both groups, the investor(s) backed individuals personally known to them, to another syndicate member, and/or to the deal referrer. When the linkage to performance is explored, both solo and syndicate serial investors are well advised to back entrepreneurs known to a least one member of the investor group