Minimizing Safety Interference for Safe and Comfortable Automated Driving with Distributional Reinforcement Learning

Despite recent advances in reinforcement learning (RL), its application in safety critical domains like autonomous vehicles is still challenging. Although punishing RL agents for risky situations can help to learn safe policies, it may also lead to highly conservative behavior. In this paper, we propose a distributional RL framework in order to learn adaptive policies that can tune their level of conservativity at run-time based on the desired comfort and utility. Using a proactive safety verification approach, the proposed framework can guarantee that actions generated from RL are fail-safe according to the worst-case assumptions. Concurrently, the policy is encouraged to minimize safety interference and generate more comfortable behavior. We trained and evaluated the proposed approach and baseline policies using a high level simulator with a variety of randomized scenarios including several corner cases which rarely happen in reality but are very crucial. In light of our experiments, the behavior of policies learned using distributional RL can be adaptive at run-time and robust to the environment uncertainty. Quantitatively, the learned distributional RL agent drives in average 8 seconds faster than the normal DQN policy and requires 83\% less safety interference compared to the rule-based policy with slightly increasing the average crossing time. We also study sensitivity of the learned policy in environments with higher perception noise and show that our algorithm learns policies that can still drive reliable when the perception noise is two times higher than the training configuration for automated merging and crossing at occluded intersections

Strategisches Management in Kommunen: Entstehung, Inhalte und Wirkungen von Digitalisierungs- und Nachhaltigkeitsstrategien

Der Beitrag untersucht Praxen des strategischen Managements in deutschen Kommunalverwaltungen am Beispiel von Digitalisierungs- und Nachhaltigkeitsstrategien. Es werden drei Forschungsfragen bearbeitet: 1. Was sind typische Inhalte und Strukturen solcher Strategien? 2. Wie und warum entstehen solche Strategien? 3. Welche Erfahrungen machen Kommunen mit diesen Strategien?

Transcriptional Response of Zebrafish Embryos Exposed to Neurotoxic Compounds Reveals a Muscle Activity Dependent hspb11 Expression

Acetylcholinesterase (AChE) inhibitors are widely used as pesticides and drugs. Their primary effect is the overstimulation of cholinergic receptors which results in an improper muscular function. During vertebrate embryonic development nerve activity and intracellular downstream events are critical for the regulation of muscle fiber formation. Whether AChE inhibitors and related neurotoxic compounds also provoke specific changes in gene transcription patterns during vertebrate development that allow them to establish a mechanistic link useful for identification of developmental toxicity pathways has, however, yet not been investigated. Therefore we examined the transcriptomic response of a known AChE inhibitor, the organophosphate azinphos-methyl (APM), in zebrafish embryos and compared the response with two non-AChE inhibiting unspecific control compounds, 1,4-dimethoxybenzene (DMB) and 2,4-dinitrophenol (DNP). A highly specific cluster of APM induced gene transcripts was identified and a subset of strongly regulated genes was analyzed in more detail. The small heat shock protein hspb11 was found to be the most sensitive induced gene in response to AChE inhibitors. Comparison of expression in wildtype, ache and sopfixe mutant embryos revealed that hspb11 expression was dependent on the nicotinic acetylcholine receptor (nAChR) activity. Furthermore, modulators of intracellular calcium levels within the whole embryo led to a transcriptional up-regulation of hspb11 which suggests that elevated intracellular calcium levels may regulate the expression of this gene. During early zebrafish development, hspb11 was specifically expressed in muscle pioneer cells and Hspb11 morpholino-knockdown resulted in effects on slow muscle myosin organization. Our findings imply that a comparative toxicogenomic approach and functional analysis can lead to the identification of molecular mechanisms and specific marker genes for potential neurotoxic compounds

Jovanka kommt an! Stadtgestaltung für einen inklusiven Campus Lichtwiese. Städtebaulicher Entwurf im Sommersemester 2017.

Der TU Darmstadt Campus Lichtwiese wird sich in den nächsten Jahrzehnten stark entwickeln. Zur Debatte stehen eines neues Mobilitätskonzept, die Neuordnung der Freiflächen und Nachverdichtung durch studentisches Wohnen. In Rahmen des Entwurfs sollen in Zusammenarbeit mit Studierenden mit eingeschränkter Mobilität, Seh- oder Höreinschränkung, und Newcomern in Darmstadt Konzepte entwickelt werden, die Zugänglichkeit und Aufenthaltsqualität des Campus (für eine der Gruppen) im Sinne des Universal Design und des Access for All erhöhen

Compositional dependence of the band-gap of Ge1−x−y_{1−x−y}Six_{x}Sny_{y} alloys

The group-IV semiconductor alloy Ge1−x−ySixSny has recently attracted great interest due to its prospective potential for use in optoelectronics, electronics, and photovoltaics. Here, we investigate molecular beam epitaxy grown Ge1−x−ySixSny alloys lattice-matched to Ge with large Si and Sn concentrations of up to 42% and 10%, respectively. The samples were characterized in detail by Rutherford backscattering/channeling spectroscopy for composition and crystal quality, x-ray diffraction for strain determination, and photoluminescence spectroscopy for the assessment of band-gap energies. Moreover, the experimentally extracted material parameters were used to determine the SiSn bowing and to make predictions about the optical transition energy

Digital uncooled IRFPAs based on microbolometers with 17 μm and 12μm pixel pitch

This paper presents the results of high-performance infrared detectors (IRFPA – InfraRed Focal Plane Array) based on uncooled microbolometers with 17 μm and 12 μm pixel pitch and a chip-scale-package as the vacuum package developed and fabricated by Fraunhofer-IMS. Like CMOS image sensor IRFPAs also have been following the trend of reducing the pixel size in order to reduce the costs and increase the optical resolution. For microbolometer based uncooled IRFPA the pixel pitch has been reduced from 35 μm pixel pitch ten years ago via 25 μm and 17 μm down to 12 μm. Fraunhofer IMS has developed digital IRFPAs featuring a direct conversion of the microbolometer’s resistance into a 16 bit value by the use of massively parallel on-chip Sigma-Delta-ADCs achieving a high scene temperature dynamic range of more than 300 K and a very low NETD-value below 50 mK. Due to a broadband antireflection coating the digital IRFPAs achieve a high sensitivity in the LWIR (wavelength 8 μm to 14 μm) and MWIR (wavelength 3 μm to 5 μm) range. In this paper the microbolometer, the vacuum-packaging, the architecture of the readout electronics, and the electro-optical performance characterization will be presented

Pharmacotherapies and Aortic Heme Oxygenase-1 Expression in Patients with Abdominal Aortic Aneurysm

Background: Treatment of cardiovascular risk factors slows the progression of small abdominal aortic aneurysms (AAA). Heme oxygenase-1 (HO-1) is a stress- and hemin-induced enzyme providing cytoprotection against oxidative stress when overexpressed. However, nothing is known about the effects of cardiometabolic standard therapies on HO-1 expression in aortic walls in patients with end-stage AAA. Methods: The effects of statins, angiotensin-converting enzyme (ACE) inhibitors, angiotensin II receptor blockers (ARBs), calcium channel blockers (CCBs), beta-blockers, diuretics, acetylsalicylic acid (ASA), and therapeutic anticoagulation on HO-1 mRNA and protein expressions were analyzed in AAA patients using multivariate logistic regression analysis and comparison of monotherapy. Results: Analysis of monotherapy revealed that HO-1 mRNA and protein expressions were higher in patients on diuretics and lower in patients on statin therapy. Tests on combinations of antihypertensive medications demonstrated that ACE inhibitors and diuretics, ARBs and diuretics, and beta-blockers and diuretics were associated with increase in HO-1 mRNA expression. ASA and therapeutic anticoagulation were not linked to HO-1 expression. Conclusion: Diuretics showed the strongest association with HO-1 expression, persisting even in combination with other antihypertensive medications. Hence, changes in aortic HO-1 expression in response to different medical therapies and their effects on vessel wall degeneration should be analyzed in future studies

Associations of Tissue and Soluble LOX‐1 with Human Abdominal Aortic Aneurysm

Background Indication for prophylactic surgical abdominal aortic aneurysm (AAA) repair depends on the maximal aortic diameter. The lectin‐like oxidized low‐density lipoprotein receptor‐1 (LOX‐1) is the major receptor for uptake of oxidized low‐density lipoprotein cholesterol and is implicated in atherosclerosis. A soluble form of LOX‐1 (sLOX‐1) has been discussed as a novel biomarker in coronary artery disease and stroke. Herein, we assessed the regulation of aortic LOX‐1 as well as the diagnostic and risk stratification potential of sLOX‐1 in patients with AAA. Methods and Results Serum sLOX‐1 was assessed in a case–control study in AAA (n=104) and peripheral artery disease (n=104). sLOX‐1 was not statistically different between AAA and peripheral artery disease but was higher in AAA (β=1.28, P=0.04) after adjusting for age, atherosclerosis, type 2 diabetes, prescription of statins, β‐blockers, ACE inhibitors, and therapeutic anticoagulation. sLOX‐1 was not associated with the aortic diameter, AAA volume, or the thickness of the intraluminal thrombus. Aortic LOX‐1 mRNA expression tended to be higher in AAA when compared with disease, and expression was positively associated with cleaved caspase‐3, smooth muscle actin, collagen, and macrophage content. Conclusions In AAA, sLOX‐1 was differently affected by age, cardiometabolic diseases, and corresponding medical therapies. Comparison with nonatherosclerotic disease would be beneficial to further elucidate the diagnostic potential of sLOX‐1, although it was not useful for risk stratification. Aneurysmal LOX‐1 mRNA expression was increased and positively associated with smooth muscle cells and collagen content, suggesting that LOX‐1 is eventually not deleterious in human AAA and could counteract AAA rupture