Cross-traffic assistance considering uncertainties in measurements and prediction

Obwohl die Statistik aufzeigt, dass sich an Kreuzungen gehäuft Unfälle ereignen, wird der Fahrer in dieser offensichtlich komplexen Situation bis dato nur in wenigen Serienfahrzeugen von Assistenzsystemen unterstützt. Eine Ursache hierfür ist die eingeschränkte Einsicht konventioneller On-Board Sensorik wie Radar und Kamera in den seitlichen Kreuzungsarm, wodurch potentiell vorhandener Querverkehr erst spät erfasst werden kann. Die Kommunikation zwischen Fahrzeugen stellt einen vielversprechenden technologischen Fortschritt zur Beherrschung kritischer Situationen im Kreuzungsbereich dar. Bei der Anwendung dieser Technologie entstehen eine Reihe von neuen Fragestellungen: Reicht die Genauigkeit der satellitengestützten Lokalisierung aus, um dem Fahrer eine möglichst falschwarnungsfreie, aber dennoch wirksame Assistenz anbieten zu können? Wie kann bei der Bewertung der Kritikalität mit den variierenden Unsicherheiten aus der Lokalisierung umgegangen werden? Welchen Einfluss nehmen die Unsicherheiten, die aus dem Fahrerverhalten resultieren? Um diese Fragen zu beantworten, wird in dieser Arbeit ein prototypisches Assistenzsystem entwickelt und im Rahmen eines Feldversuchs mit Probanden getestet. Die Messdaten dienen einerseits dazu, durch Expertenanalyse und Fahrerbefragung Optimierungspotential des bestehenden Systems zu identifizieren und liefern andererseits eine umfangreiche Datenbasis für die Evaluierung von neuen Ansätzen. Dies stellt die Grundlage dar für die im weiteren Verlauf entwickelten Methoden zur Handhabung von Unsicherheiten aus Fahrerverhalten und Sensorik. Die Abbiegeabsicht wird mit einem neuartigen Ansatz bewertet, der aus Sicht des Fahrers mehrere mögliche Manöver plant. Anhand der zeitlichen Entwicklung der optimalen Überführungskosten der geplanten Trajektorien wird auf die Abbiegeabsicht des Fahrers geschlossen. Das Verfahren wird anhand zahlreicher realer Abbiegemanöver evaluiert. Es kann gezeigt werden, dass eine verlässliche Detektion bereits zu einem Zeitpunkt möglich ist, welcher dem Fahrer eine hinreichend große Reaktionszeitreserve ermöglicht, um eine kritische Situation selbst zu entschärfen. Der Umgang mit den Unsicherheiten aus der Sensorik gelingt, indem zunächst zeitbasierte Kriterien zur Bewertung der Kritikalität im deterministischen Fall untersucht werden. Anschließend wird mit Hilfe der Methode der exakten Monome und mehrdimensionaler Gauß-Quadratur eine recheneffiziente Approximation für den probabilistischen Fall vorgeschlagen.Traversing an intersection is a challenging task for human drivers. Vehicle accident statistics, which provide evidence of this adverse circumstance, indicate an increased frequency of accidents. However, advanced driver assistance systems that provide assistance during intersection situations are not available in all series production cars. Among other reasons this is due to the reduced detection range of conventional sensors, such as radar or cameras for vehicles on lateral crossroads. Cross-traffic assistance based on vehicle-to-vehicle communication technology exhibits promising attributes for the control of this type of situation because crossing traffic can be detected even without a line-of-sight. However, the application of this technology introduces the following new issues: Is the precision of satellite based positioning sufficiently accurate to provide effective assistance to a driver while maintaining a low false-positive warning rate? What is the best approach to coping with the varying uncertainty of localization measurements during criticality assessment? How is the uncertainty about the intention of the driver related to this issue? To answer these questions, a prototype system is developed and extensively tested during a field-operational test using naive probands. The acquired data enables the optimization of the current system via analysis by experts and driver surveys. The data also serves as an extensive data base for the evaluation of the new algorithms developed in this thesis, which focus both on the uncertainty in the driver’s behavior and in measurement. Turning maneuver intention is estimated by a novel approach, in which several possible maneuvers are planned from the viewpoint of the driver. To infer the intended maneuver, the gradient of the optimal cost-to-go of each planned trajectory is employed. This approach is evaluated with numerous turning maneuvers and enables early and reliable detection of the actual conducted maneuver, which facilitates an effective warning. The ability to handle measurement uncertainty is addressed by examining time-based criticality measures for the deterministic case. Subsequently, an efficient approximation for the probabilistic case, which is based on a method of exact monomials and multidimensional Gaussian quadrature, is proposed

The type-2 Streptococcus canis M protein SCM-2 binds fibrinogen and facilitates antiphagocytic properties

Streptococcus canis is a zoonotic agent that causes severe invasive diseases in domestic animals and humans, but little is known about its pathogenesis and virulence mechanisms so far. SCM, the M-like protein expressed by S. canis, is considered one of the major virulence determinants. Here, we report on the two distinct groups of SCM. SCM-1 proteins were already described to interact with its ligands IgG and plasminogen as well as with itself and confer antiphagocytic capability of SCM-1 expressing bacterial isolates. In contrast, the function of SCM-2 type remained unclear to date. Using whole-genome sequencing and subsequent bioinformatics, FACS analysis, fluorescence microscopy and surface plasmon resonance spectrometry, we demonstrate that, although different in amino acid sequence, a selection of diverse SCM-2-type S. canis isolates, phylogenetically representing the full breadth of SCM-2 sequences, were able to bind fibrinogen. Using targeted mutagenesis of an SCM-2 isolate, we further demonstrated that this strain was significantly less able to survive in canine blood. With respect to similar studies showing a correlation between fibrinogen binding and survival in whole blood, we hypothesize that SCM-2 has an important contribution to the pathogenesis of S. canis in the host

Travel-associated neurological disease terminated in a postmortem diagnosed atypical HSV-1 encephalitis after high-dose steroid therapy - a case report

Background: Human encephalitis can originate from a variety of different aetiologies, of which infection is the most common one. The diagnostic work-up is specifically challenging in patients with travel history since a broader spectrum of unfamiliar additional infectious agents, e. g. tropical disease pathogens, needs to be considered. Here we present a case of encephalitis of unclear aetiology in a female traveller returning from Africa, who in addition developed an atypical herpes simplex virus (HSV) encephalitis in close temporal relation with high-dose steroid treatment. Case presentation: A previously healthy 48-year-old female presented with confusion syndrome and impaired vigilance which had developed during a six-day trip to The Gambia. The condition rapidly worsened to a comatose state. Extensive search for infectious agents including a variety of tropical disease pathogens was unsuccessful. As encephalitic signs persisted despite of calculated antimicrobial and antiviral therapy, high-dose corticosteroids were applied intravenously based on the working diagnosis of an autoimmune encephalitis. The treatment did, however, not improve the patient's condition. Four days later, bihemispheric signal amplification in the insular and frontobasal cortex was observed on magnetic resonance imaging (MRI). The intracranial pressure rapidly increased and could not be controlled by conservative treatment. The patient died due to tonsillar herniation 21 days after onset of symptoms. Histological examination of postmortem brain tissue demonstrated a generalized lymphocytic meningoencephalitis. Immunohistochemical reactions against HSV-1/2 indicated an atypical manifestation of herpesviral encephalitis in brain tissue. Moreover, HSV-1 DNA was detected by a next-generation sequencing (NGS) metagenomics approach. Retrospective analysis of cerebrospinal fluid (CSF) and serum samples revealed HSV-1 DNA only in specimens one day ante mortem. Conclusions: This case shows that standard high-dose steroid therapy can contribute to or possibly even trigger fulminant cerebral HSV reactivation in a critically ill patient. Thus, even if extensive laboratory diagnostics including wide-ranging search for infectious pathogens has been performed before and remained without results, continuous re-evaluation of potential differential diagnoses especially regarding opportunistic infections or reactivation of latent infections is of utmost importance, particularly if new symptoms occur

SROI (Social Return on Investment) – A Case Study about Social Profit

Abstract—In annual accounts and management reports, financial figures are used predominantly both in commercial and nonprofit companies in order to give a true and fair view of a company's assets, profits and financial position. As a result, the financial success is a key performance indicator – a figure which, usually, is quite low in the case of nonprofit companies [1]. However, such companies strive to reach content-oriented goals primarily, for instance performance quality, training success and employee satisfaction. As content-oriented goals are their basis of legitimacy, there should be possibilities to calculate whether they are met [2]. Basic prerequisite for such a calculation are specified details about the company’s mission statement, its content-oriented goals (from an economic, business, social or environmental point of view), its commercial goals (concerning profitability, liquidity and financial security) and its standards to measure objectives [3]. On this basis, it becomes possible to set targets and to incorporate the defined goals into a monitoring and reporting system [4]. Beyond achieving a profit, a social kind of success becomes interesting in such cases, which can be expressed as the so-called Social Profit. For example, this key figure can be measured by comparing costs and benefits attributed to the support of people in need. Benefits calculations takes avoided social spending into account, for example due to the prevention of homelessness, imprisonment or psychiatric clinic stays. The calculation also takes account of the effects of an individual’s rehabilitation and restored working abilities on the partaking in working and social life – which in the long run benefit society as a whole as well as tax payers [5]. Company goals, target groups, possible activities and their effects are of interest to calculate the Social Profit. However, several assumptions must be made about future political and economic developments. The following case study approaches to define and apply the concept “Social Profitâ€.   Index Terms: Content-oriented objectives, Impact, Legitimation, Private and public investments, Social economy enterprises, Social Profit, Social Return on Investmen