Do retailers benefit from the long tail phenomenon?

The Internet and related technologies have vastly expanded the variety of products that can be profitably promoted and sold by online retailers. As a result, while in most offline markets, a few best selling products (blockbusters) generate the bulk of demand, online demand for blockbusters is often accompanied by sales for a huge number of less-selling products (niches). In response to emerging long-tailed sales distribution patterns, Anderson (2004, 2006) coined the phrase Long Tail to describe the phenomenon that niche products can gain a significant share in total sales. Most important from a retailers' perspective is whether additionally offered niche products mainly substitute former existing ones or if consumers expand their demand. While the latter can generate additional profit, substitution is only beneficial if substitutes have higher margins than products that were purchased before. By using a unique data set of a monopolistic video-on-demand operator in Germany that covers all individual sales since its launch from December 2004 until August 2007, we disentangle demand for additional offered films into substitution and additional consumption. Our results reveal that demand of additionally offered films is driven by on average 86.10% additional consumption and only 13.90% substitution, suggesting huge profit potential for retailers by increasing their assortments. © 2010 IADIS

Mapping with Skysat Images

The very high-resolution space imagery now competes with some functions that were previously solved with aerial images. Several very high-resolution optical satellites with a ground sampling distance (GSD) of 1 m and smaller are currently active. Not all of these satellites take images worldwide. Nevertheless, it is not a problem to obtain up-to-date satellite images with a very high resolution. Mapping projects not only need to consider access and quality, but also cost-effectiveness. Of course, the economic framework conditions are decisive for the decision as to whether space images or very high-resolution satellite images should be used. With a total 21 SkySat satellites, low-cost satellites with very high resolution have changed the economic conditions. To keep costs and weights down, the Skysat satellites were not designed to offer the best direct geo-referencing performance, but this problem can be solved by automatic orientation in relation to existing orthoimages.In North Rhine-Westphalia, the cadastral maps must be checked at regular intervals to ensure that the buildings are complete. A test project examined whether this is possible with SkySat images. The geometric conditions and the image quality with the effective ground resolutions are investigated. Experiences from earlier publications could not be used. First the specific problem had to be solved, the resolution of the SkySat images was improved by lowering the satellite orbit altitude from 500 km to 450 km and by a better super resolution with 0.50 m ground sampling distance for the SkySat Collect orthoimages and in addition Planet improved their generation of Collect images. The required standard deviation of the object details of 4 m was achieved clearly as the effective ground resolution of 0.5 m if the angle of incidence is below 20°

ReS²tAC—UAV-borne real-time SGM stereo optimized for embedded ARM and CUDA devices

With the emergence of low-cost robotic systems, such as unmanned aerial vehicle, the importance of embedded high-performance image processing has increased. For a long time, FPGAs were the only processing hardware that were capable of high-performance computing, while at the same time preserving a low power consumption, essential for embedded systems. However, the recently increasing availability of embedded GPU-based systems, such as the NVIDIA Jetson series, comprised of an ARM CPU and a NVIDIA Tegra GPU, allows for massively parallel embedded computing on graphics hardware. With this in mind, we propose an approach for real-time embedded stereo processing on ARM and CUDA-enabled devices, which is based on the popular and widely used Semi-Global Matching algorithm. In this, we propose an optimization of the algorithm for embedded CUDA GPUs, by using massively parallel computing, as well as using the NEON intrinsics to optimize the algorithm for vectorized SIMD processing on embedded ARM CPUs. We have evaluated our approach with different configurations on two public stereo benchmark datasets to demonstrate that they can reach an error rate as low as 3.3%. Furthermore, our experiments show that the fastest configuration of our approach reaches up to 46 FPS on VGA image resolution. Finally, in a use-case specific qualitative evaluation, we have evaluated the power consumption of our approach and deployed it on the DJI Manifold 2-G attached to a DJI Matrix 210v2 RTK unmanned aerial vehicle (UAV), demonstrating its suitability for real-time stereo processing onboard a UAV

Prevalence in Primary School Youth of Pica and Rumination Behavior: The Understudied Feeding

Objective: Little epidemiological evidence exists on rumination disorder behavior (RB) and pica behavior (PB). We examined prevalence of RB and PB and presence of comorbid feeding/eating disorder symptoms among school-aged children. Methods: In elementary schools in Switzerland, 1,430 children (54.0% female) ages seven to 13 completed Eating Disorder Examination-Questionnaire for children (ChEDE-Q) and Eating Disturbances in Youth Questionnaire (EDY-Q). Results: EDY-Q data behavior frequency showed 9.7% reported RB only, 10.0% reported PB only, and 3.1% reported RB+PB (≥1 on 0-6 Likert scale). At a clinical cut-off score of ≥4 (at least “often true”), 1.7% had RB only, 3.8% had PB only, and 1.1% had RB+PB. Avoidant/restrictive food intake disorder symptoms were most common in those with RB+PB, and more common in those with RB or PB than those without. Degree of eating disorder symptoms (by ChEDE-Q) over the past 28 days were similar among those with RB, PB, or RB+PB, but less common in those without RB or PB. Discussion: RB and PB were commonly reported in our sample of school-aged children, even at a potential clinically significant cut-off. Our findings also suggest that degree of eating disorder symptom comorbidity is similar between those with RB and PB

Pre-Discovery 2007 Image of the HR 8799 Planetary System

We present a pre-discovery H-band image of the HR 8799 planetary system that reveals all three planets in August 2007. The data were obtained with the Keck adaptive optics system, using angular differential imaging and a coronagraph. We confirm the physical association of all three planets, including HR 8799d, which had only been detected in 2008 images taken two months apart, and whose association with HR 8799 was least secure until now. We confirm that the planets are 2-3 mag fainter than field brown dwarfs of comparable near-infrared colors. We note that similar under-luminosity is characteristic of young substellar objects at the L/T spectral type transition, and is likely due to enhanced dust content and non-equilibrium CO/CH_4 chemistry in their atmospheres. Finally, we place an upper limit of 18 mag per square arc second on the >120 AU H-band dust-scattered light from the HR 8799 debris disk. The upper limit on the integrated scattered light flux is 1e-4 times the photospheric level, 24 times fainter than the debris ring around HR 4796A.Comment: ApJ Letters, in press; 13 pages, 3 figures, 1 tabl