Investigating Full-Waveform Lidar Data for Detection and Recognition of Vertical Objects

A recent innovation in commercially-available topographic lidar systems is the ability to record return waveforms at high sampling frequencies. These “full-waveform” systems provide up to two orders of magnitude more data than “discrete-return” systems. However, due to the relatively limited capabilities of current processing and analysis software, more data does not always translate into more or better information for object extraction applications. In this paper, we describe a new approach for exploiting full waveform data to improve detection and recognition of vertical objects, such as trees, poles, buildings, towers, and antennas. Each waveform is first deconvolved using an expectation-maximization (EM) algorithm to obtain a train of spikes in time, where each spike corresponds to an individual laser reflection. The output is then georeferenced to create extremely dense, detailed X,Y,Z,I point clouds, where I denotes intensity. A tunable parameter is used to control the number of spikes in the deconvolved waveform, and, hence, the point density of the output point cloud. Preliminary results indicate that the average number of points on vertical objects using this method is several times higher than using discrete-return lidar data. The next steps in this ongoing research will involve voxelizing the lidar point cloud to obtain a high-resolution volume of intensity values and computing a 3D wavelet representation. The final step will entail performing vertical object detection/recognition in the wavelet domain using a multiresolution template matching approach

Extracting spatial information : grounding, classifying and linking spatial expressions

This paper is concerned with the tagging of spatial expressions in German newspaper articles, assigning a meaning to the expression and classifying the usages of the spatial expression and linking the derived referent to an event description. In our system, we implemented the activation of concepts in a very simple fashion, a concept is activated once (with a cost depending on the item that activated it) and is left activated thereafter. As an example, a city also activates the nodes for the region and the country it is part of, so that cities from one country are chosen over cities from different countries. A test corpus of 12 German newspaper articles was tested regarding several disambiguation strategies. Disambiguation was carried out via a beam search to find an approximately cost-optimal solution for the conflict set of potential grounding candidates for the tagged spatial expression. Test showed that the disambiguation strategies improved accuracy significantly

The Gender Gap Cracks Under Pressure: A Detailed Look at Male and Female Performance Differences During Competitions

Using data from multiple-period math competitions, we show that males outperform females of similar ability during the first period. However, the male advantage is not found in any subsequent period of competition, or even after a two-week break from competition. Some evidence suggests that males may actually perform worse than females in later periods. The analysis considers various experimental treatments and finds that the existence of gender differences depends crucially on the design of the competition and the task at hand. Even when the male advantage does exist, it does not persist beyond the initial period of competition.competitiveness, gender differences, effort and productivity, field experiment

Causes of Gender Differences in Competition: Theory and Evidence

We use a game theoretic model of contests to assess different explanations for the male performance advantage in competition. Comparing the testable predictions of the model with the empirical evidence, we reject explanations involving male overcon- fidence, misperceptions about relative ability, and some preference differences. Ex- planations involving female underconfidence, stereotype threat, and adverse female reaction to competition are consistent with only some of the evidence, and an expla- nation involving lower male risk aversion is consistent with most of the evidence. Two explanations are consistent with all of the evidence: (i) male ability to perform may in- crease in the face of competition, possibly due to changes in testosterone or adrenaline; or (ii) males may care more about winning or get greater enjoyment from competition than females.contests, gender differences, effort and productivity

Chromospherically active stars in the ROTSE-1 database: paper 6. Variables 126 - 149

Another 24 new chromospherically active stars are presented, which were found in the ROTSE-1 database: GSC 02268-00394, GSC 01224-00894, GSC 00648-00579, GSC 02865-01987, GSC 01851-01202, GSC 00124-00551, GSC 00150-01109, GSC 01339-00572, GSC 02968-01511, GSC 03005-00885, GSC 01083-00698, GSC 03941-00354, GSC 04450-00134, GSC 05163-01764, GSC 01095-00848, GSC 04459-00659, USNO A2.0 1275-14029063, GSC 04247-00903, GSC 01656-01276, GSC 02197-01430, GSC 02227-01294, GSC 04480-00965, GSC 01159-00245, GSC 02237-01574. For one of these stars (GSC 00124-00551), further observations were made using a TeleView 509/5.0 telescope with a CCD camera SIGMA1603 and IR-cutting filter in Velden, Germany

An inequality of Kostka numbers and Galois groups of Schubert problems

We show that the Galois group of any Schubert problem involving lines in projective space contains the alternating group. Using a criterion of Vakil and a special position argument due to Schubert, this follows from a particular inequality among Kostka numbers of two-rowed tableaux. In most cases, an easy combinatorial injection proves the inequality. For the remaining cases, we use that these Kostka numbers appear in tensor product decompositions of sl_2(C)-modules. Interpreting the tensor product as the action of certain commuting Toeplitz matrices and using a spectral analysis and Fourier series rewrites the inequality as the positivity of an integral. We establish the inequality by estimating this integral.Comment: Extended abstract for FPSAC 201