Disagreement on expectations: firms versus consumers

This paper evaluates the dynamic response of economic activity to shocks in agents’ perception of uncertainty. The study focuses on the comparison between manufacturers’ and consumers’ perception of economic uncertainty, gauged by a geometric discrepancy indicator to quantify the proportion of disagreement in eleven European countries and the Euro Area. A vector autoregressive framework is used to estimate the impulse response functions to innovations in disagreement, both for manufacturers and consumers. The effect on economic activity of shocks to the perception of uncertainty is found to differ markedly between both types of agents. On the one hand, shocks to consumer discrepancy tend to be of greater magnitude and duration than those to manufacturer discrepancy. On the other hand, innovations in disagreement between the two collectives have an opposite effect on economic activity: shocks to manufacturer discrepancy lead to a decrease in economic activity, as opposed to shocks to consumer discrepancy. This finding is of particular relevance to researchers when using cross-sectional dispersion of survey-based expectations for approximating and assessing economic uncertainty, since the effect on economic growth of shocks to disagreement may be dependent on the type of agent and the way in which expectations have been elicited.

Rigorous Co-Registration of KOMPSAT-3 Multispectral and Panchromatic Images for Pan-Sharpening Image Fusion

KOMPSAT-3, a Korean earth observing satellite, provides the panchromatic (PAN) band and four multispectral (MS) bands. They can be fused to obtain a pan-sharpened image of higher resolution in both the spectral and spatial domain, which is more informative and interpretative for visual inspection. In KOMPSAT-3 Advanced Earth Imaging Sensor System (AEISS) uni-focal camera system, the precise sensor alignment is a prerequisite for the fusion of MS and PAN images because MS and PAN Charge-Coupled Device (CCD) sensors are installed with certain offsets. In addition, exterior effects associated with the ephemeris and terrain elevation lead to the geometric discrepancy between MS and PAN images. Therefore, we propose a rigorous co-registration of KOMPSAT-3 MS and PAN images based on physical sensor modeling. We evaluated the impacts of CCD line offsets, ephemeris, and terrain elevation on the difference in image coordinates. The analysis enables precise co-registration modeling between MS and PAN images. An experiment with KOMPSAT-3 images produced negligible geometric discrepancy between MS and PAN images.

Comparative Study of the Fit Accuracy of Full-Arch Bar Frameworks Fabricated with Different Presintered Cobalt-Chromium Alloys

Purpose. This study was to measure the geometric discrepancies that occur during the sintering contraction of presintered Co-Cr alloys in a full-arch bar framework and to compare the variations between alloys from different manufacturers. Materials and Methods. Eighteen implant-supported full-arch bar frameworks were fabricated through a soft-machining process using presintered Co-Cr alloy blocks: Ceramill Sintron (CS), Soft Metal (SM), and Sintermetall (SML) (n=6 for each group). The sintered frameworks were digitized using a structured light scanner, and the scan images were superimposed on the reference design. The geometric discrepancies of the sintered frameworks were three-dimensionally analyzed for horizontal, angular, and internal discrepancies. Kruskal-Wallis and Mann–Whitney U tests were used to compare the discrepancies among the groups (α=.05). Results. Significant differences were found in the geometric discrepancy measurements among the groups. The CS group showed larger horizontal and angular discrepancies, followed by the SM and SML groups (P<.001). The root mean square (RMS) values for internal discrepancy were not statistically different among the groups (P=.778). Conclusion. The geometric discrepancies of full-arch bar frameworks fabricated using the soft-machining process were affected by accuracies in sintering contraction of presintered alloys.

Davenport's theorem in geometric discrepancy theory

Davenport's theorem was established nearly a lifetime ago, but there have been some very interesting recent developments. The various proofs over the years bring in different ideas from number theory, probability theory, analysis and group theory. In this short survey, we shall not present complete proofs, but will describe instead some of these underlying ideas.