Identification of Lane-Change Maneuvers in Real-World Drivings with Hidden Markov Model and Dynamic Time Warping

For the introduction of new automated driving functions, the systems need to be verified extensively. A scenario-driven approach has become an accepted method for this task. But to verify the functionality of an automated vehicle in the simulation in a certain scenario such as a lane change, relevant characteristics of scenarios need to be identified. This, however, requires to extract these scenarios from real-world drivings accurately. For that purpose, this work proposes a novel framework based on a set of unsupervised learning methods to identify lane-changes on motorways. To represent various types of lane changes, the maneuver is split up into primitive driving actions with an Hidden Markov Model and Divisive Hierarchical Clustering. Based on this, lane change maneuvers are identified using Dynamic-Time-Warping. The presented framework is evaluated with a real-world test drive and compared to other baseline methods. With a f1 score of 98.01\% in lane-change identification, the presented approach shows promising results

Temperature sensitivity of soil organic matter decomposition after forest fire in Canadian permafrost region

Climate warming in arctic/subarctic ecosystems will result in increased frequency of forest fires, elevated soil temperatures and thawing of permafrost, which have implications for soil organic matter (SOM) decomposition rates, the CO2 emissions and globally significant soil C stocks in this region. It is still unclear how decomposability and temperature sensitivity of SOM varies in different depths and different stages of succession following forest fire in permafrost regions and studies on long term effects of forest fires in these areas are lacking. To study this question, we took soil samples from 5, 10 and 30 cm depths from forest stands in Northwest Canada, underlain by permafrost, that were burnt by wildfire 3, 25 and over 100 years ago. We measured heterotrophic soil respiration at 1, 7, 13 and 19 °C. Fire had a significant effect on the active layer depth, and it increased the temperature sensitivity (Q10) of respiration in the surface (5 cm) and in the deepest soil layer (30 cm) in the 3-year-old area compared to the 25- and more than 100-year-old areas. Also the metabolic quotient (qCO2) of soil microbes was increased after fire. Though fires may facilitate the SOM decomposition by increasing active layer depth, they also decreased SOM quality, which may limit the rate of decomposition. After fire all of these changes reverted back to original levels with forest succession.Peer reviewe

Recovery of carbon stocks after wildfires in boreal forests : a synthesis

Book of abstracts Cool forests at risk? The Critical Role of Boreal and Mountain Ecosystems for People, Bioeconomy, and ClimatePeer reviewe

Fire-induced changes of high and low intensity prescribed fires in a Canadian boreal forest

Geophysical Research AbstractsVol. 21, EGU2019-7859, 2019EGU General Assembly 2019The degree of fire-induced effects on boreal forest soils substantially depends on the intensityof fire. Especially high-intensity fires may drastically alter the quality and quantity of the soilorganic matter pool. In this study, we investigated the effects of low and high intensityprescribed fires on soil carbon and nitrogen contents, soil pH, soil temperature, and soilmoisture in a Canadian boreal forest. The study was based on intensive field sampling duringAugust 2018 in Jack pine (Pinus banksiana) forest stands located 50 km north of FortProvidence, Northwest Territories (61.582˚ ; -117.165˚). We measured the soil parametersfrom two short-term fire chronosequences — one with high-intensity prescribed fireshappening in years 2000, 2012, 2015, 2016, and 2017; and the other with low-intensityprescribed fires happening in years 2015, 2017, and 2018. Additionally, we measured soiltemperature and moisture before and after a low-intensity prescribed fire. In thehigh-intensity fire chronosequence, the study site burned in year 2012 had the lowest soiltemperature. Even though temperatures seemed slightly higher in the most recent years ofthe fire chronosequence (2015, 2016, and 2017), we did not identify a clear trend.Soil moisture was the lowest in the study site burned in year 2000, with mostly nosignificant differences between the following years. We did not find significantdifferences in soil moisture and soil temperature before and after a low-intensityprescribed fire. However, both time-after-fire and fire intensity were important forsoil moisture prediction, whereas only fire intensity was important for predictingsoil temperature. Soil pH in the humus layer of the study site burned in 2012 wassignificantly lower compared to the other age classes (no pH data for year 2000) of thehigh-intensity fire chronosequence. Neither C nor N content were significantly differentbetween the fire age classes at the humus layer or at the mineral layers. We believethat the small sample size did not allow the identification of further differencesbetween the age classes, and it prevented direct comparisons between high and lowintensity fires. Despite its exploratory nature, this study offers some insight intoshort-term effects of fire on some soil parameters, for example, the observed changeson soil moisture, soil temperature, and soil pH. Therefore, we will progress thiswork by increasing the sample size and analysing autotrophic and heterotrophic soilrespiration to directly infer on fire-induced changes on the soil organic matter pool.Non peer reviewe

Soil organic matter decomposition and temperature sensitivity after forest fire in permafrost regions in Canada

Non peer reviewe

Application Platform for Intelligent Mobility (AIM) and Testbed Lower Saxony

Currently test-environments for automated driving are set-up in several countries. As the mobility system shows a lot of complexity, which is even increased by the introduction of CCAV, it is very difficult to cover all the different aspects and to answer the open questions in one test environment. It is therefore essential to align the activities in the different test environments and to learn from each other. This presentation presents the Test Bed Lower Saxony for automated and connected mobility, i.e. its technical capabilities, modes of operation for the test environments, test scenarios and use cases