Semantic technologies for the domain specific and formal description of time series in databases

Messdaten werden zur effizienten Organisation und Weiterverarbeitung in relationalen Datenbanken gespeichert. Die in den letzten Jahren entstandenen Semantic Web Technologien bieten eine hervorragende Basis zur Wissensmodellierung und Beschreibung von Domäneninhalten in Form von Ontologien. Aufgrund der offenen Architektur dieses Ansatzes können leicht fremde Ontologien und Ressourcen mit eingebunden und berücksichtigt werden. Semantic Web Technologien stellen eine formale Modellierungsgrundlage dar. Mittels Reasoning kann deshalb aus Ontologien implizites Wissen abgeleitet werden. In dieser Arbeit werden semantische (Datenbank-) Annotationen und deren Interpretation fokussiert. Sie verknüpfen Datenbanken und das Semantic Web miteinander. Die Annotationen erlauben es, Inhalte von Datenbanken mit Semantic Web Technologien in verschiedenen Nutzungsszenarien zu beschreiben. Außerdem wird für die gemeinsame Behandlung und den Einsatz beider Technologien eine Architektur entwickelt. Auf dieser Basis werden Konzepte zur Visualisierung und Interaktion mit den Annotationen eingeführt. Weiterhin wird deren Einsatz zur formalen Modellierung von Ereignissen mittels Automaten betrachtet, sodass ein Reasoning zur Berechnung durchgeführt werden kann. Mittels einer Implementierung werden die eingeführten Konzepte demonstriert. Die Applikation Semantic Database Browser erlaubt die integrierte Verwendung von Messdaten und deren formaler Beschreibung. Modelle können ausgetauscht und wiederverwendet werden, sodass die Wiederverwendung von Wissen gefördert wird. Anhand des Beispiels von Ereignissen während Autofahrten wird demonstriert, wie auf Basis der formalen Beschreibung Schlussfolgerungen gezogen werden können. So können durch das Schlussfolgern ohne zusätzlichen Aufwand neue Erkenntnisse über auftretende Fahrmanöver generiert werden. Aufgrund des domänenunabhängigen Charakters der skizzierten Lösungsansätze wird gezeigt, dass diese sich leicht auf andere Anwendungsfälle anwenden lassen.Measurement data in form of time series of scientific experiments is stored in relational databases for efficient processing. Complementary, Semantic Web technologies have been developed in the last years for describing domain knowledge in form of ontologies. Due to their open architecture, foreign ontologies and resources can be easily referenced and integrated. Since Semantic Web technologies are based on predicate logic, they are suitable for formal modeling. Therefore, using reasoning implicit knowledge can be derived from ontologies. This work introduces semantic (database) annotations to link databases and ontologies to take advantage of both together by describing database contents with Semantic Web technologies. An architecture is developed for the combined handling and usage of these two technologies, which is designed in respect of scalability of large amounts of measurement data. Based on this architecture, concepts for visualizing and interacting with annotations are introduced. Furthermore, semantic annotations are used for formally modeling events in time series using finite state machines, which are computed using reasoning. An implementation is introduced to demonstrate the feasibility and advantages of the discussed concepts. The presented application Semantic Database Browser allows using semantic database annotations and interactively working with them for integrated handling of formally described measurement data. Formal models can be easily exchanged and reused to support reusability of knowledge and cooperation. By describing measurement data with models, data becomes much easier to understand. Using an example of events during driving, it is demonstrated how formal description can be used for automatic reasoning to generate additional knowledge about driving maneuvers without any additional effort. Because the presented approaches are domain independent, they can be easily adapted for other use cases

Managing delays and incidents at intermodal airport hubs in a more efficient way

Der Beitrag untersucht verschiedene Möglichkeiten des Verspätungsmanagements an intermodalen Hubflughäfen. Im Ergebnis ist ein kooperativer Ansatz zwischen allen Stakeholdern sowohl aus verkehrlicher als auch aus ökonomischer Sicht von Vorteil

Leistungsfähiges Datenmanagement als Rückgrat einer menschzentrierten Entwicklung von Automation/Assistenz

Empirische Studien, die damit verbundenen Daten und darauf durchgeführte Analysen sind wichtige Bausteine in menschzentrierten Entwicklungsprozessen für moderne Assistenz- und Automationssysteme. Hiermit verknüpfte Forschungs- und Entwicklungsaktivitäten setzen ein leistungsfähiges Datenmanagement voraus, welches neben der Handhabung der erhobenen Rohdaten auch die Verarbeitung von Metadaten als eine zentrale Aufgabe begreift. Über die unmittelbare Datennutzung hinaus, lassen sich mit Hilfe geeigneter Metadaten u.a. auch langfristig angelegte Studien (Akzeptanzstudien / Naturalistic Driving Studies) und komplexe/verteilte Analyseszenarien effektiv unterstützen. Zudem wird der Einsatz automatischer Datenanalysetechniken (Data Mining) durch ein adäquat konzipiertes Metadatenmanagement vorbereitet bzw. ermöglicht

Simulating a multi-airport region on different abstraction levels by coupling several simulations

Airports build the pillar for international mobility and are core elements of intermodal traffic. They are interface between ground level transportation and air transport and commonly act as central points for logistics. The DLR project "Optimode.net" investigates the interaction between relevant traffic modes and develops innovative approaches for integrated traffic management of ground and air level. The realization of an integration traffic planning is the foundation for several research questions, how the interaction between planes and ground transport can be improved. While the overall airport management benefits from more efficiency, travelers should be supported with a door-to-door management service. The simulated scenario consists of four cities in a multi airport region. The simulation of the region includes three airports in different sizes with the simulation of the feeder traffic to the airport. All cities are connected by road and railroad and public ground level transport is available. The procedure switching between a ground level vehicle and a plane needs several time consuming steps at the airport for individual passengers, including security checks, boarding and so on. Therefore these steps are also simulated at the airport on a passenger level. Furthermore the dispositioning of flights must be considered. On the ground level individual traffic, public road transport and railways are included in the simulation environment. In total the complete simulation environment is built of nine simulation models with various abstraction levels. For the simulation of ground level vehicles in this environment SUMO is used. This paper discusses the coupling and the data exchange between of the different simulators and further focuses on the integration of SUMO in this setup

Teile und herrsche - Tabellenpartitionierung in PostgreSQL

Bei Datenbanken hat sich Tabellenpartitionierung als ein Mittel zur Beherrschung der wachsenden Datenmengen etabliert. Mit den aktuellen Versionen bietet auch PostgreSQL diese nützliche Fähigkeit

Generation of Highway Sections for Automated Test Case Creation

Creating proper tracks for simulation including logical representation is usually a demanding, time consuming, iterative and manual task using classical visual scenario editors. On the contrary, creating and managing multiple variants of tracks varying in details is needed to build virtual test cases, which become especially important with regard to automated driving and its enormous test requirements. From this background manual test scenario creation becomes quickly overwhelming. Consequently, approaches for automated creation of tracks for testing purposes are needed. This paper presents a solution to create various tracks automatically covering a huge variety of characteristics. It uses a lightweight description to minimize definition effort done either manually or derived methodologically . This work is embedded in the PEGASUS project (www.pegasusprojekt.de/en) that is investigating generally accepted quality criteria, tools and methods as well as scenarios and situations for the release of highly-automated driving functions. PEGASUS is funded by the Federal Ministry for Economic Affairs and Energy (BMWi). In the PEGASUS project it was decided to use OpenDRIVE (www.opendrive.org) as an open and mature XML-based file format for the topological and topographical description of road networks, which is vendor-independent, contains all features to model real road networks and is supported by commonly used simulation software. Therefore, OpenDRIVE is a natural choice to model virtual tracks for test cases. In combination with OpenSCENARIO (www.openscenario.org) for describing dynamic behavior of objects and participants these two formats build a solid foundation to model environments for virtual test cases. It is a proven approach to use domain-specific languages (DSL) to reduce complexity and increase efficiency for testing purposes [Deursen]. This is also the chosen way for the presented solution, as OpenDRIVE is powerful but also quite complex. Modelling efforts can be reduced significantly by the introduction of such an abstraction layer into the prototyping toolchain of OpenDRIVE. It has to be expected that first scenarios of highly automated driving will occur on highways [Bartels]. Consequently, this fact allows in a first stage to focus on modelling highways and their characteristics in a DSL. Highways are usually not built at will, but follow strict rules and guidelines. For example, in Germany the "Richtlinie für die Anlage von Autobahnen" (RAA, [RAA]) defines possible cross sections, allowed markings and combination of longitudinal courses and other properties of highways. With this domain-specific knowledge bundled in a DSL it should be possible to rapidly increase efficiency of modelling realistic virtual highways for test cases. Another approach uses tiles containing street sections and surrounding objects based on standardized edges such as applied in the ENABLE-S3 project (www.enable-s3.eu). These tiles can be easily and quickly combined by a user to create larger areas. Obviously, this approach drastically increases productivity of a user. But on the contrary, as tiles must be combinable, the content near the edges has quite strict limitations, which result in rather unnatural street courses of the created maps. For limited scenarios (e.g. parking decks) this approach can be still valid though. The presented background leads to the research question for this paper: Can a DSL be used to efficiently model variants of highways to create (adequately realistic tracks) to describe test cases? The methodology used for this examination covers the following steps based on an experimental approach. To investigate this question, first the needed elements of highways were identified and are used to create a first version of a DSL called SimplifiedRoad. As next step, a transformation engine for SimplifiedRoad into OpenDRIVE was created. With these foundations the approach to use a DSL for describing highways for test cases can be evaluated. Especially aspects of usability, efficiency and proper modelling are investigated. The next sections discuss the results of our work. As relevant content from the road construction guidelines several attributes for describing the appearance of the road as well as the road infrastructure "on top" were identified: number of lanes and their width, line markings, course, elevation, lateral profile, traffic signs and environmental objects. A fundamental design goal of SimplifiedRoad is to be as similar to OpenDRIVE as possible without applying the complexity of OpenDRIVE to SimplifiedRoad. Especially some optional enhancements are introduced in addition to OpenDRIVE: SimplifiedRoad allows mirroring roads with a simple attribute and furthermore pre-defined cross sections can be applied. With this additions simple road segments can be described already with very few lines. Furthermore, meaningful default values are used for all elements where possible. For example, default coordinates of street segments are generated at the end of previous segments. Environmental objects like guide posts, guard rails or noise barriers are typically used repeatedly and consist of several individual elements, what is simplified. An important feature is the possibility to allow parametrization of attributes in a SimplifiedRoad file. That is especially helpful to manage several variants of a track with slight differences (e.g. different street widths). Another feature to be implemented in the near future is the integration of highway entries and exits based on guidelines and a possibility of modification, too. The implementation of the transformation tool is straightforward from this background. With SimplifiedRoad first test track results show a reduction of required lines and characters to just 10 % of the generated OpenDRIVE. Especially parametrization of these files has the potential to boost productivity further. The final conclusion is that using a DSL to efficiently model highway sections for test cases is a good choice. It must be admitted, that a format like OpenDRIVE was likely never designed to be edited manually. Compared with a visual track editor using a DSL editor has different challenges for the user, but also using the visual editor is not always intuitive to model correct logic. Using a DSL does not replace classical scenario editors, but complements certain use case creation. It can be expected that in future DSLs will gain importance for creation of virtual tracks for test cases

Efficient modelling of highway tracks for test case creation

For the construction of test catalogues for tests by simulation, one needs flexible and efficient means to define road layouts. A widely used and mature format for road layouts for simulation is the XML based OpenDRIVE. In combination with OpenSCENARIO for describing dynamic behavior of traffic participants and environment, these two forthcoming ASAM standards provide means for defining virtual test cases. This contribution explores the potential of DSLs, in particular approaches like SimplifiedROAD, to realize higher levels of abstraction. It first presents enhancements of SimplifiedROAD which extend the set of available features. It goes on to announce elements and structures which are going to further raise the level of abstraction. Third, it discusses concepts which on the basis of these additions permit to define road layouts in a natural language style

Digitaler Hafen: Moderne Hafenregelung durch Simulation

In dieser Arbeit wird das Potential von "digitalen Häfen" als intermodale Verkehrsknoten analysiert und bewertet. Für diese Betrachtungen werden mehrere parallellaufende Simulatoren in einer integrierenden Architektur gekoppelt, um den bodengebundenen Verkehr, die Personenbewegungen und den Schiffsverkehr gemeinsam zu simulieren. Beim Umschlag am Hafen durchlaufen die Waren und Güter aber auch Passagiere mehrere Prozesse. Die Start- und Endzeiten der Prozesse werden für die anschließende Bewertung durch Meilensteine beschrieben. Werden diese Meilensteine sinnvoll über die Prozesse miteinander in Relation gesetzt, so lassen sich daraus effizient Kennzahlen (KPIs) bestimmen. Die relevanten Meilensteine und die Berechnung der KPIs zur Auswirkungsanalyse werden vorgestellt und definiert