Semantically Guided Depth Upsampling

We present a novel method for accurate and efficient up- sampling of sparse depth data, guided by high-resolution imagery. Our approach goes beyond the use of intensity cues only and additionally exploits object boundary cues through structured edge detection and semantic scene labeling for guidance. Both cues are combined within a geodesic distance measure that allows for boundary-preserving depth in- terpolation while utilizing local context. We model the observed scene structure by locally planar elements and formulate the upsampling task as a global energy minimization problem. Our method determines glob- ally consistent solutions and preserves fine details and sharp depth bound- aries. In our experiments on several public datasets at different levels of application, we demonstrate superior performance of our approach over the state-of-the-art, even for very sparse measurements.Comment: German Conference on Pattern Recognition 2016 (Oral

Energy-efficient Reactive and Predictive Connected Cruise Control

In this paper, we propose a framework for the longitudinal control of connected and automated vehicles traveling in mixed traffic consisting of connected and non-connected human-driven vehicles. Reactive and predictive controllers are proposed. Reactive controllers are given by explicit feedback control laws. In predictive controllers, the control input is optimized in a receding-horizon fashion, which depends on the predictions of motions of preceding vehicles. Beyond-line-of-sight information is obtained via vehicle-to-vehicle (V2V) communication, and is utilized in the proposed reactive and predictive controllers. Simulations utilizing real traffic data are used to show that connectivity can bring significant energy savings.Comment: 18 pages, 12 figures, submitted to Transportation Research Part C: Emerging Technologie

Growth by destination: the role of trade in Africa's recent growth episode

Over the period 1990–2009, Africa has experienced a distinct and favourable reversal in its growth fortunes in stark contrast to its performance in the preceding decades, leading to a variety of hypotheses seeking to explain the phenomenon. This paper presents both cross-country and panel-data evidence on the causal factors driving the recent turnaround in Africa's growth and takes the unique approach of disaggregating the separate growth impacts of Africa's bilateral trade with: China, Europe and America. The empirical analysis presented in this paper suggests that the primary and most robust causal factors driving Africa's recent growth turnaround are private sector- and foreign direct investment. Although empirical evidence of the role of bilateral trade openness in Africa's recent growth emerges within a fixed effect estimation setting, these results are not as robust when endogeneity and other issues are fully accounted for. Among the three major bilateral partners, Africa's bilateral trade with China has been a relatively important factor spurring growth on the continent and especially so in resource-rich, oil producing and non-landlocked countries. The econometric results are not as supportive of growth-inducing effects of foreign aid. These findings emerge after applying a variety of panel data specifications to the data, including the recent fixed Effects Filtered (FEF) estimator introduced by Pesaran and Zhou (2014) and the dynamic panel Generalized Method of Moments (GMM) estimator, which allows for endogeneity between trade and growth

Time dependent Doppler shifts in high-order harmonic generation in intense laser interactions with solid density plasma and frequency chirped pulses

High order harmonic generation from solid targets is a compelling route to generating intense attosecond or even zeptosecond pulses. However, the effects of ion motion on the generation of harmonics have only recently started to be considered. Here, we study the effects of ion motion in harmonics production at ultrahigh laser intensities interacting with solid density plasma. Using particle-in-cell simulations, we find that there is an optimum density for harmonic production that depends on laser intensity, which scales linearly with a(0) with no ion motion but with a reduced scaling if ion motion is included. We derive a scaling for this optimum density with ion motion and also find that the background ion motion induces Doppler red-shifts in the harmonic structures of the reflected pulse. The temporal structure of the Doppler shifts is correlated to the envelope of the incident laser pulse. We demonstrate that by introducing a frequency chirp in the incident pulse we are able to eliminate these Doppler shifts almost completely. (C) 2015 AIP Publishing LLC