Guido Gehlen

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The role of the service oriented architecture (SOA) is going to he more and more popular in the software design for distributed systems. This middleware framework tries to simplify as much as possible the software architecture of distributed applications. In infrastructure based networks like the Internet the SOA is successfully implemented by XML Web(More)
A Web service based middleware for mobile applications is a promising platform to accelerate the application development for mobile systems. Currently, the Web service protocol stack is using by default the simple object access protocol (SOAP) on top of HTTP. Since HTTP is using TCP, the round-trip time of a Web service call in mobile networks is high due(More)
Communication within and from a vehicle is a key function for various vehicle applications, like telematics, logistics, and traffic control applications. This paper describes the flexible and extendable architecture of a vehicle communication gateway which acts as a central communication device embedded in the vehicle and managing the in-vehicle,(More)
Context information is vital data coming from mobile devices to add a value for the application execution. Such applications are called context-aware or context-sensitive applications. To enable context-aware applications in a distributed environment, first the context raw data is measured from sensors. After interpreting and structuring the data, the(More)
Context information is one of the most important data coming from, mobile devices to add a value for the application execution. This paper introduces a context dissemination middleware based on a mobile Web services framework. In a P2P environment, each context source/provider offers services to other devices. A monitor service is proposed which reduces the(More)
A novel architecture is proposed that enables the detection, automatic priority-based processing and validation of event messages, and data fusion of periodically gathered probe data to facilitate various Intelligent Transportation System (ITS) applications. Floating car data and mobile phone data are processed in a multilevel Event Validator service to(More)
MobilitY and CollAboRative Work in European Vehicle Emergency NeTworks (MYCAREVENT)1 is an European Project of the 6th Framework Program [1]. MYCAREVENT aims to optimize the European market for automotive services and repair. MYCAREVENT develops and implements new applications and services, which can be seamlessly and securely, accessed using mobile(More)
In this article we look at the scenario of mobile nodes, e.g. cars, which are connected to a back-end system and an application running on the mobile back-end system which wants to monitor data of the mobile nodes, e.g. the position data of the cars. There are many options to realize such an application, but we have to take care of the costs and performance(More)
We describe a layered evaluation approach to assess the accuracy of traffic speed estimation based on floating phone data. We designed a simulation framework to investigate the influence of various parameters on the estimation. Multiple quality metrics and combinations of metrics have been used and intervals of metric values have been mapped to quality(More)