Christoph Terwelp

Product oriented integration of heterogeneous mobility services

Growing spontaneous mobility demand and decreasing affinity to automobile ownership in young generations require integrated concepts for intermodal mobility. Especially in areas with insufficient capacity coverage by traditional public transport, adding alternative services, e.g. car sharing, seems promising. Currently, customers have to combine different means of transportation manually by checking several information sources, creating a combined itinerary and booking several, mode specific tickets. This paper presents an information system architecture, the so-called Mobility Broker, a joint platform for mobility services that enables provider collaboration to offer travelers the best possible combined service. Mobility Broker combines heterogeneous mobility service data, like time tables and car sharing places, using standardized open interfaces and well-known methods of data integration. The combined information allows intermodal routing for generating combined itineraries. Furthermore, it allows to use one ticket for heterogenous travelings. By this simplification of access to intermodal travel, we aim to foster the integration of alternative public transport modes. Thereby, the heterogeneous mobility service product characteristics and related synergy effects determine the approach fundamentally.

Landmark-based navigation in complex buildings

Growing numbers of mobile devices in our daily life and their capability to fulfill challenging computational tasks raise the question about new application fields beyond well-established tasks. While outdoor navigation became a standard task for many mobile devices, indoor positioning and navigation is still in the research and development stage. Even though complex buildings require aided guidance for visitors, todays mobile hardware is not able to deliver a reliable indoor navigation system. In this paper we describe a novel information system for indoor navigation in complex buildings. Users are guided through the building by using images of the surroundings and textual instructions. We avoid hardware-based user positioning due to its known drawbacks. Instead, users are involved into the navigation process and complete missing information through recognized context and logical constrains of their surroundings. The human navigation process based on recognition of certain unique locations and visual clues is the foundation of this work. The proposed system is universally applicable without restrictions on navigation devices or existing hardware in the building.

Indoor navigation approach based on approximate positions

Until now navigation aids have primarily focused on outdoor scenarios, whether driving on highways or, more recently, walking through cities. These systems use the Global Positioning System (GPS) for position information. Indoor navigation however cannot rely on GPS data, as the signals do not penetrate building structure. Thus other techniques were developed to provide position information indoors, but most of them lack the precision of GPS. In this article the approach of an indoor navigation system based on imprecise position information is presented. To compensate the deficit of precision the position information is combined with a movement model. This movement model is automatically generated from the maps which are already required for navigation.

IXSI - Interface for X-Sharing Information

The increasing demand for mobility, especially for individual transport, leads to more pollution, congested cities and shortage of parking. New ways of mobility could mitigate these issues. Unfortunately, such forms of mobility, i.e. carsharing, are usually isolated services, because of the missing integration with other mobility modes. Our aim is to offer a combination of heterogeneous services on a single platform. We argue that such an integration allows optimal offers and higher usability and therefore results with a higher acceptance among travelers. Embedding a vehicle rental system into a travel information system information-wise is a step forward. For this purpose, we developed an interface for x-sharing information, short IXSI, specialized in connecting vehicle rental systems with a travel information system. IXSI is an XML-based, B2B interface with functions for, e.g., exchanging basic vehicle data and price information. The interface enables travel information systems to perform bookings of carsharing and bikesharing vehicles and therefore allows the customer to use traditional public transport services as well as rental services seamlessly. Furthermore, we briefly present our IXSI implementations on travel information and vehicle rental system side.

ProMoX: A protocol stack monitoring framework

In this paper, we present a preliminary glance on our framework for protocol stack monitoring using Xen (ProMoX). ProMoX uses the Xen hypervisor to virtualize entire instances of operating systems which may execute any arbitrary protocol implementation. By utilizing system virtualization for external monitoring, ProMoX can transparently inspect any protocol state and performance metrics of protocol implementations carried by a guest operating system. This way, ProMoX supports both the indentification of faults within early prototypes as well as the evaluation of new protocol designs.

Heterogeneous Travel Information Exchange

Travel information brokers are complex systems, dealing with a large amount of heterogeneous data from various sources. The exchange and integration of such data is therefore demanding, particularly for small mobility service providers with few IT resources. To face this problem, this work illustrates a key tool to support information and service integration. On a conceptual level, we present a travel information broker system architecture and respective information flows. Additionally, we describe data exchange related to system components, e.g., intermodal routing, pricing and accounting. On this basis, we developed and tested a communication adapter that enables and eases communication between the core system and second party service providers. Furthermore we outline the method of extending public transportation routing with information about sharing services. This enables travelers to query combined information about public transport, bikesharing as well as carsharing services using a single application.

Device Whispering: An Approach for Directory-Less WLAN Positioning

A widely-used positioning system for mobile devices is GPS. It is based on transit times of signals from satellites, so it provides accurate positioning in outdoor scenarios. But in indoor scenarios it is not usable because the signals are absorbed by buildings. To provide positioning services indoors several approaches exist which use for example GSM (Global System for Mobile Communication) or WLAN (Wireless Local Area Network) signals. GSM based systems not using special hardware are limited to identify the GSM-Cell the mobile device is in and associate it through a directory service with a geographical position. The fingerprinting approach is based on WLAN using signal strength vectors of multiple access points to approximate a position. But this method requires a huge number of measurements and only works reliable in laboratory environments. The approach discussed in this paper uses the WLAN radio of a mobile device to identify the nearest access point. Then the geographical position of the mobile device is calculated from the geo tags broadcasted by the access points. So the approach provides at least the same accuracy as directory-based positioning systems but does not require the maintenance and communication costs of a directory. The evaluation shows that the accuracy of this approach is limited by the abilities of hardware and drivers on todays mobile devices.

Information Integration for Advanced Travel Information Systems

ATIS (Advanced Travel Information Systems) are complex systems, dealing with a large amount of heterogeneous data from various sources. The exchange and integration of such data is therefore demanding, particularly for small mobility service providers with few IT (Information Technology) resources. To face this problem, this work illustrates an IT infrastructure to support information and service integration. On a conceptual level, this paper presents a travel information system architecture and respective information flows between components, e.g., intermodal routing, pricing and accounting. As realization, the authors developed and tested a communication adapter that enables and eases information exchange between the ATIS and heterogeneous second party service providers, e.g., carsharing operators. Furthermore, the authors developed a method of extending traditional public transportation routing using the exchanged information about sharing services. This enables travelers to query intermodal itinerary information combining public transport, bikesharing as well as carsharing services using a single application. The overall system was tested in a three-month testing phase. Initial results are promising.

Mobility Service Platforms - Cross-Company Cooperation for Transportation Service Interoperability.

The growing number of modes of transportation with diverse characteristics and situational suitability would allow a multifaceted mobility behavior. Unfortunately, the usage of a combination of heterogeneous modes of transportation – specifically during a complex travel chain with multiple changeovers – is hindered in various ways. Users have to query, compare, combine, book and use multiple specialized mobility service individually which results in inefficiencies both on demand and supply side. Centralized mobility service platforms can form a technological bridge to deliver service interoperability. In cross section between competition and cooperation, the need for suitable, profitable, and sustainable market forms to provide complex service configurations arises. As a result of interdisciplinary workshops with domain experts, we describe a role relationship model and identify relevant market forms. To do so, we present a conceptional tool to analyze, characterize and differentiate various mobility service platforms and apply it to set of platforms currently beeing developed.

Randomised Optimisation of Discrimination Networks Considering Node-sharing

Because of their ability to efficiently store, access, and process data, Database Management Systems (DBMSs) and Rule-based Systems (RBSs) are used in many information systems as information processing units. A basic function of a RBS and a function of many DBMSs is to match conditions on the available data. To improve performance intermediate results are stored in Discrimination Networks (DNs). The resulting memory consumption and runtime cost depend on the structure of the DN. A lot of research has been done in the area of optimising DNs. In this paper, we focus on re-using network parts considering multiple rule conditions and exploiting the characteristics of equivalences. We present an approach incorporating the potential of both concepts and balance their application in a randomised fashion. To evaluate the algorithms developed, they were implemented and yielded promising results. Shortcomings of this approach are discussed and their removal constitutes our current work.