Overview of vehicle-to-vehicle radio channel measurements for collision avoidance applications

In this paper we present an overview of a vehicle-to-vehicle radio channel measurement campaign at 5.6GHz. The selected measurement scenarios are based on important safety-related applications. We explain why these scenarios are interesting from the aspect of radio propagation. Further we describe the power-delay profile and the Doppler spectral density of two situations especially suitable for collision avoidance applications: A traffic congestion situation where one car is overtaking another one, and a general line-of-sight obstruction between the transmitter and the receiver car. The evaluations show that in these situations the radio channel is highly influenced by the rich scattering environment. Most important scatterers are traffic signs, trucks, and bridges, whereas other cars do not significantly contribute to the multipath propagation

BAERLIN2014 - stationary measurements and source apportionment at an urban background station in Berlin, Germany

The Berlin Air quality and Ecosystem Research: Local and long-range Impact of anthropogenic and Natural hydrocarbons (BAERLIN2014) campaign was conducted during the 3 summer months (June–August) of 2014. During this measurement campaign, both stationary and mobile measurements were undertaken to address complementary aims. This paper provides an overview of the stationary measurements and results that were focused on characterization of gaseous and particulate pollution, including source attribution, in the Berlin–Potsdam area, and quantification of the role of natural sources in determining levels of ozone and related gaseous pollutants. Results show that biogenic contributions to ozone and particulate matter are substantial. One indicator for ozone formation, the OH reactivity, showed a 31% (0.82±0.44s−1) and 75% (3.7±0.90s−1) contribution from biogenic non-methane volatile organic compounds (NMVOCs) for urban background (2.6±0.68s−1) and urban park (4.9±1.0s−1) location, respectively, emphasizing the importance of such locations as sources of biogenic NMVOCs in urban areas. A comparison to NMVOC measurements made in Berlin approximately 20 years earlier generally show lower levels today for anthropogenic NMVOCs. A substantial contribution of secondary organic and inorganic aerosol to PM10 concentrations was quantified. In addition to secondary aerosols, source apportionment analysis of the organic carbon fraction identified the contribution of biogenic (plant-based) particulate matter, as well as primary contributions from vehicles, with a larger contribution from diesel compared to gasoline vehicles, as well as a relatively small contribution from wood burning, linked to measured levoglucosan

Identifying core features of adaptive metabolic mechanisms for chronic heat stress attenuation contributing to systems robustness

The contribution of metabolism to heat stress may play a significant role in defining robustness and recovery of systems; either by providing the energy and metabolites required for cellular homeostasis, or through the generation of protective osmolytes. However, the mechanisms by which heat stress attenuation could be adapted through metabolic processes as a stabilizing strategy against thermal stress are still largely unclear. We address this issue through metabolomic and transcriptomic profiles for populations along a thermal cline where two seagrass species, Zostera marina and Zostera noltii, were found in close proximity. Significant changes captured by these profile comparisons could be detected, with a larger response magnitude observed in northern populations to heat stress. Sucrose, fructose, and myo-inositol were identified to be the most responsive of the 29 analyzed organic metabolites. Many key enzymes in the Calvin cycle, glycolysis and pentose phosphate pathways also showed significant differential expression. The reported comparison suggests that adaptive mechanisms are involved through metabolic pathways to dampen the impacts of heat stress, and interactions between the metabolome and proteome should be further investigated in systems biology to understand robust design features against abiotic stress

Combination of Lidar and Model Data for Studying Deep Gravity Wave Propagation

The paper presents a feasible method to complement ground-based middle atmospheric Rayleigh lidar temperature observations with numerical simulations in the lower stratosphere and troposphere to study gravity waves. Validated mesoscale numerical simulations are utilized to complement the temperature below 30-km altitude. For this purpose, high-temporal-resolution output of the numerical results was interpolated on the position of the lidar in the lee of the Scandinavian mountain range. Two wintertime cases of orographically induced gravity waves are analyzed. Wave parameters are derived using a wavelet analysis of the combined dataset throughout the entire altitude range from the troposphere to the mesosphere. Although similar in the tropospheric forcings, both cases differ in vertical propagation. The combined dataset reveals stratospheric wave breaking for one case, whereas the mountain waves in the other case could propagate up to about 40-km altitude. The lidar observations reveal an interaction of the vertically propagating gravity waves with the stratopause, leading to a stratopause descent in both cases

Entwicklung eines Stereokamerasystemszur Objekterkennung undEntfernungsbestimmung in mobilenRobotersystemen

Mobile Robotersysteme müssen ein Modell ihrer Umgebung erstellen, um Hindernisse oder Missionsziele zu erkennen. Auf der Grundlage eines solchen Modells werden Aktionen geplant und ausgeführt. Neben Laserscannern, Ultraschallsensoren und weiteren Techniken bietet die Erfassung der Umwelt mit Videokameras eine flexible Alternative. Am Beispiel des humanoiden Roboters " Mr. DD" der Darmstadt Dribblers wird in dieser Diplomarbeit ein neues, passives Stereokamerasystem entwickelt, welches zur Objekterkennung und Abstandsbestimmung verwendet wird. Hierfür kommen erstmalig zwei einfache USB-Webcams zum Einsatz. Weiterhin werden verschiedene Algorithmen zur Kalibrierung des Systems, Farbsegmentierung und Positionsberechnung untersucht und die geeignetsten implementiert. Ein Hauptkriterium für die Verwendbarkeit der Algorithmen ist die begrenzte Rechenleistung mobiler Robotersysteme. Da die untersuchten Algorithmen zu langsam sind, werden schließlich zwei neue merkmalsbasierte Verfahren zur Korrespondenzberechnung entwickelt. Die Leistungsfähigkeit des Stereokamerasystems wird in der definierten Umgebung eines RoboCup-Feldes demonstriert, in welcher zum Beispiel der Ball relativ zu den Kameras lokalisiert wird. Abstract: Mobile robots need a model of their environment to detect obstacles or mission goals. Using such a model actions are planned and executed. Besides laser scanners, ultrasonic detectors and other technologies video cameras are a flexible alternative. Using the humanoid robot " Mr. DD" of the Darmstadt Dribblers a new passive stereo vision system is developed in this diploma thesis, which is used for object recognition and distance measurements. For the first time two simple USB webcams are employed for this purpose. Furthermore different algorithms for calibrating the system, color segmentation and position estimation are investigated and the most suitable are implemented. A main criterion for the applicability of the algorithms is the limited computing power of mobile robots. Two new feature based methods for calculating correspondences are eventually developed because the investigated algorithms are too slow. The abilities of the stereo vision system are demonstrated in the defined environment of a RoboCup field where the ball is localized relative to the cameras as proof of concept