Improved Railway Track Irregularities Classification by a Model Inversion Approach
Over time railway networks have become complex Systems characterized by manifold types of technical components with a broad range of age distribution. De facto, about 50 percent of the life cycle costs of railway infrastructures are made up by direct and indirect maintenance costs. A remedy can be provided by a condition based preventive maintenance strategy leading to an optimized scheduling of maintenance actions taking the actual aswell as the expected future infrastructure condition into account. A prerequisite is, however, that the thousands of Kilometers of railway tracks are almost continuously monitored. Thus, a promising approach is the usage of low-cost sensors, e.g. accelerometers and gyroscopes, which can be installed on common in-line freight and passenger trains. Due to ambiguous data records a credible classification of railway track irregularities directly from these data is challenging. Alternatively to this pure data-driven approach, in this paper a novel hybrid Approach is presented. To this end, a simplified vehicle Suspension model is applied for the purpose of railway track condition monitoring by analyzing the dynamic railway track - Train interactions. The inversion of the model can be used to recalculate the actual inputs (irregularities) of the monitored system (rail surface) which have caused recorded System Responses (dynamic vehicle reactions and acceleration data, respectively). These recalculated inputs are a sound Basis of subsequent data-driven condition monitoring analyses. In this preliminary study, a classification algorithm is implemented to identify a simulated railway track irregularity automatically.
In-service condition monitoring of rail tracks: On an on-board low-cost multi-sensor system for condition based maintenance of railway tracks
Kostengunstige, nachrustbare Multi-Sensor-Systeme auf Schienenfahrzeugen ermoglichen die kontinuierliche Zustandsuberwachung des Gleisoberbaus im regularen Betrieb. Veranderungen und Schaden konnen somit fruhzeitig erkannt, Wartungsarbeiten dementsprechend durchgefuhrt und teure Ausfalle vermieden werden. Vom Deutschen Zentrum fur Luft- und Raumfahrt (DLR) wird seit 2015 ein Prototyp-System auf einer Rangierlokomotive im Braunschweiger Hafen im operativen Einsatz erprobt. Dieses Sensorsystem ermoglicht die 
georeferenzierte Aufnahme von Achslagerbeschleunigungen, die Aufschluss uber den Zustand des Schienennetzes geben. Der so 
gemessene, umfangreiche Datensatz ist die Grundlage fur die laufende Entwicklung und Erprobung von Sensorfusions- und Datenverarbeitungsalgorithmen am DLR. In diesem Artikel werden einige dieser Ansatze vorgestellt und Datenbeispiele aus dem operativen Einsatz gezeigt. Die Ergebnisse zeigen, dass relevante Streckeneigenschaften erkannt und lokalisiert werden konnen.
The Value Base of Social Work
Abstract Values may be conceived along three basic dimensions which would account for the major value orientations shared by social workers and related to all aspects of their professional practice. These are: preferred conceptions of people, preferred outcomes for people, and preferred instrumentalities for dealing with people. Distinguished from “knowledge,” and adequately refined, these categories of values might constitute a guide for planning and action in social work practice and education. The predictability of professional behavior which might then result would also define the expectations of clients and society with respect to what the social work profession stands for and what it does.