Gulliver: Design and Implementation of a Miniature Vehicular System

Traffic increases all over the world and problems such as toxic emissions and congestion are consequences of that. To encounter those problems and to optimize traffic throughput and safety, a miniature vehicular test platform that can be used together with simulation tools can be very useful. This project deals with the construction, control, communication and navigation of the autonomous 1:8 scale miniature vehicles used in the Gulliver project. The goal is to make the vehicles drive along a generated route, do lane changing between routes and to write software to interface with these vehicles. Part of the work has been spent on a custom motor controller used to control brushless DC motors, for which many safety mechanisms were implemented. Other areas covered include the fusion of several sensors with Ranging and Communication Modules to achieve indoor localization and algorithms to drive the vehicle autonomously along a pre-defined route while accepting high-level commands such as stop, go and change lanes from external sources. Another part of the project was to evaluate the high-level commands using MICAz motes that run a virtual service agent to act as virtual traffic lights. At the end all of the goals were achieved and the vehicles were able to drive along a route and accept commands from the MICAz motes. This is very useful as many details that not always are covered by pure simulations can be included while it is much easier and less costly than the same implementation with full-scale vehicles

Simulations of Mixed Morphology Supernova Remnants With Anisotropic Thermal Conduction

We explore the role of anisotropic thermal conduction on the evolution of supernova remnants through interstellar media with a range of densities via numerical simulations. We find that a remnant expanding in a dense environment can produce centre-bright hard x-ray emission within 20 kyr, and centre-bright soft x-ray emission within 60 kyr of the supernova event. In a more tenuous environment, the appearance of a centre-bright structure in hard x-rays is delayed until about 60 kyr. The soft x-ray emission from such a remnant may not become centre bright during its observable lifetime. This can explain the observations that show that mixed-morphology supernova remnants preferentially occur close to denser, molecular environments. Remnants expanding into denser environments tend to be smaller, making it easier for thermal conduction to make larger changes in the temperatures of their hot gas bubbles. We show that the lower temperatures make it very favorable to use high-stage ions as diagnostics of the hot gas bubbles in SNRs. In particular, the distribution of O VIII transitions from shell-bright at early epochs to centre-bright at later epochs in the evolution of an SNR expanding in a dense ISM when the physics of thermal conduction is included.Comment: 8 pages, 5 figures, submitted to Monthly Notice

Innovation und Verwaltungsreform

In Staat und Verwaltung werden immer wieder Modernisierungslücken festgestellt, zum Beispiel im Umgang mit der digitalen Transformation, mit der Vernetzung von Akteuren, Organisationen und Sektoren oder in Bezug auf Themen wie Agilität oder Partizipation von Bürger:innen. Mit dem Schließen dieser Modernisierungslücken ist die Hoffnung verbunden, öffentliche Aufgaben effektiver, effizienter und transparenter zu erfüllen sowie die Problemlösungskapazitäten in Staat und Verwaltung zu erhöhen. Vor diesem Hintergrund wird in letzter Zeit wieder verstärkt darüber diskutiert, wie durch Public Sector Innovations neue Arbeitsweisen, Prozesse und Strukturen geschaffen werden können, um diesen Herausforderungen zu begegnen. Mit dem vorliegenden Themenschwerpunkt wird das Ziel verfolgt, sich konzeptionell-theoretisch wie qualitativ-empirisch mit neueren Dynamiken, Einflussfaktoren und Konsequenzen von Innovationen und Reformen auf Strukturen, Arbeitsweisen und Logiken in Staat und Verwaltung zu befassen. Die Autor:innen leisten mit ihren differenzierten Detailanalysen und -ergebnissen zu den Themen Verwaltungsdigitalisierung, Innovationslabore und Agilität einen wichtigen Beitrag zu einer anhaltenden Debatte.Public sector organisations have repeatedly shown deficits in terms of modernisation and renewal, for example in adapting to digital transformation, managing interaction among stakeholders, organisations, and sectors, and addressing issues such as agility and citizen participation. Eliminating these deficits is associated with the hope that public services will be provided more effectively, efficiently, and transparently, and that the problem-solving capacities of government and public administration will be improved. In light of these challenges, there has been a growing discourse on how innovations in the public sector can foster new ways of working, processes and structures. This special issue aims to explore recent dynamics, influencing factors, and consequences of innovations and reforms on structures, working methods, and logics within government and public administration, from both conceptual and theoretical perspectives, as well as qualitative-empirical viewpoints. With their differentiated analyses and detailed findings on topics such as administrative digitalisation, innovation labs, and agility, the authors significantly contribute to this ongoing debate

Genomics yields biological and phenotypic insights into bipolar disorder

Bipolar disorder is a leading contributor to the global burden of disease(1). Despite high heritability (60-80%), the majority of the underlying genetic determinants remain unknown(2). We analysed data from participants of European, East Asian, African American and Latino ancestries (n=158,036 cases with bipolar disorder, 2.8 million controls), combining clinical, community and self-reported samples. We identified 298 genome-wide significant loci in the multi-ancestry meta-analysis, a fourfold increase over previous findings(3), and identified an ancestry-specific association in the East Asian cohort. Integrating results from fine-mapping and other variant-to-gene mapping approaches identified 36 credible genes in the aetiology of bipolar disorder. Genes prioritized through fine-mapping were enriched for ultra-rare damaging missense and protein-truncating variations in cases with bipolar disorder(4), highlighting convergence of common and rare variant signals. We report differences in the genetic architecture of bipolar disorder depending on the source of patient ascertainment and on bipolar disorder subtype (type I or type II). Several analyses implicate specific cell types in the pathophysiology of bipolar disorder, including GABAergic interneurons and medium spiny neurons. Together, these analyses provide additional insights into the genetic architecture and biological underpinnings of bipolar disorder

Dissecting the Shared Genetic Architecture of Suicide Attempt, Psychiatric Disorders, and Known Risk Factors

Background Suicide is a leading cause of death worldwide, and nonfatal suicide attempts, which occur far more frequently, are a major source of disability and social and economic burden. Both have substantial genetic etiology, which is partially shared and partially distinct from that of related psychiatric disorders. Methods We conducted a genome-wide association study (GWAS) of 29,782 suicide attempt (SA) cases and 519,961 controls in the International Suicide Genetics Consortium (ISGC). The GWAS of SA was conditioned on psychiatric disorders using GWAS summary statistics via multitrait-based conditional and joint analysis, to remove genetic effects on SA mediated by psychiatric disorders. We investigated the shared and divergent genetic architectures of SA, psychiatric disorders, and other known risk factors. Results Two loci reached genome-wide significance for SA: the major histocompatibility complex and an intergenic locus on chromosome 7, the latter of which remained associated with SA after conditioning on psychiatric disorders and replicated in an independent cohort from the Million Veteran Program. This locus has been implicated in risk-taking behavior, smoking, and insomnia. SA showed strong genetic correlation with psychiatric disorders, particularly major depression, and also with smoking, pain, risk-taking behavior, sleep disturbances, lower educational attainment, reproductive traits, lower socioeconomic status, and poorer general health. After conditioning on psychiatric disorders, the genetic correlations between SA and psychiatric disorders decreased, whereas those with nonpsychiatric traits remained largely unchanged. Conclusions Our results identify a risk locus that contributes more strongly to SA than other phenotypes and suggest a shared underlying biology between SA and known risk factors that is not mediated by psychiatric disorders.Peer reviewe

Testing Safety-Critical Systems using Fault Injection and Property-Based Testing

Testing software-intensive systems can be challenging, especially when safety requirements are involved. Property-Based Testing (PBT) is a software testing technique where properties about software are specified and thousands of test cases with a wide range of inputs are automatically generated based on these properties. PBT does not formally prove that the software fulfils its specification, but it is an efficient way to identify deviations from the specification. Safety-critical systems that must be able to deal with faults, without causing damage or injuries, are often tested using Fault Injection (FI) at several abstraction levels. The purpose of FI is to inject faults into a system in order to exercise and evaluate fault handling mechanisms. The aim of this thesis is to investigate how knowledge and techniques from the areas of FI and PBT can be used together to test functional and safety requirements simultaneously. We have developed a FI tool named FaultCheck that enables PBT tools to use common FI-techniques directly on source code. In order to evaluate and demonstrate our approach, we have applied our tool FaultCheck together with the commercially available PBT tool QuickCheck on a simple and on a complex system. The simple system is the AUTOSAR End-to-End (E2E) library and the complex system is a quadcopter simulator that we developed ourselves. The quadcopter simulator is based on a hardware quadcopter platform that we also developed, and the fault models that we inject into the simulator using FaultCheck are derived from the hardware quadcopter platform. We were able to efficiently apply FaultCheck together with QuickCheck on both the E2E library and the quadcopter simulator, which gives us confidence that FI together with PBT can be used to test and evaluate a wide range of simple and complex safety-critical software.This research has been funded through the PROWESS EU project (Grant agreement no: 317820), the KARYON EU project (Grant agreement no: 288195) and through EISIGS (grants from the Knowledge Foundation).PROWESSKARYO

On the Design and Testing of Dependable Autonomous Systems

Designing software-intensive embedded systems for dependable autonomous applications is challenging. In addition to fulfilling complex functional requirements, the system must be safe under all operating conditions, even in the presence of faults. The key to achieving this is by simulating and testing the system enough, including possible faults that can be expected, to be confident that it reaches an acceptable level of performance with preserved safety. However, as the complexity of an autonomous system and its application grows, it becomes exponentially more difficult to perform exhaustive testing and explore the full state space, which makes the task a significant challenge. Property-Based Testing (PBT) is a software testing technique where tests and input stimuli for a system are automatically generated based on specified properties of the system, and it is normally used for testing software libraries. PBT is not a formal proof that the system fulfills the specified properties, but an effective way to find deviations from them. Safety-critical systems that must be able to deal with hardware faults are often tested using Fault Injection (FI) at several abstraction levels. The purpose of FI is to inject faults into a system in order to exercise and evaluate fault handling mechanisms. In this thesis, we utilize techniques from PBT and FI, for automatically testing functional and safety requirements of autonomous system simultaneously. We have done this on both simulations of hardware, and on real-time hardware for autonomous systems. This has been done in the process of developing a quadcopter system with collision avoidance, as well as when developing a self-driving model car. With this work we explore how tests can be auto-generated with techniques from PBT and FI, and how this approach can be used at several abstraction levels during the development of these systems. We also explore which details and design choices have to be considered while developing our simulators and embedded software, to ease testing with our proposed methods

A Low-Cost Model Vehicle Testbed with Accurate Positioning for Autonomous Driving

Accurate positioning is a requirement for many applications, including safety-critical autonomous vehicles. To reduce cost and at the same time improving accuracy for positioning of autonomous vehicles, new methods, tools and research platforms are needed. We have created a low-cost testbed consisting of electronics and software, that can be fitted on model vehicles allowing them to follow trajectories autonomously with a position accuracy of around 3 cm outdoors. The position of the vehicles is derived from sensor fusion between Real-Time Kinematic Satellite Navigation (RTK-SN), odometry and inertial measurement, and performs well within a 10 km radius from a base station. Trajectories to be followed can be edited with a custom GUI, where also several model vehicles can be controlled and visualized in real time. All software and Printed Circuit Boards (PCBs) for our testbed are available as open source to make customization and development possible. Our testbed can be used for research within autonomous driving, for carrying test equipment, and other applications where low cost and accurate positioning and navigation is required. © 2018 Benjamin Vedder et al

Using Simulation, Fault Injection and Property-Based Testing to Evaluate Collision Avoidance of a Quadcopter System

In this work we use our testing platform based on FaultCheck and QuickCheck that we apply on a quadcopter simulator. We have used a hardware platform as the basis for the simulator and for deriving realistic fault models for our simulations. The quadcopters have a collision-avoidance mechanism that shall take over control when the situation becomes hazardous, steer away from the potential danger and then give control back to the pilot, thereby preventing collisions regardless of what the pilot does. We use our testing platform to randomly generate thousands of simulations with different input stimuli (using QuickCheck) for hundreds of quadcopters, while injecting faults simultaneously (using FaultCheck). This way, we can effectively adjust system parameters and enhance the collision-avoidance mechanism. © 2015 IEEEThis research has been funded through the PROWESS EU project (Grant agreement no: 317820), the KARYON EU project (Grant agreement no: 288195) and through EISIGS (grants from the Knowledge Foundation).PROWESSKARYO