Gerhard Trippen

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How efficiently can we search an unknown environment for a goal in unknown position? How much would it help if the environment were known? We answer these questions for simple polygons and for general graphs, by providing online search strategies that are as good as the best offline search algorithms, up to a constant factor. For other settings we prove(More)
We consider the problem of a searcher that looks, for example, for a lost flashlight in a dusty environment. The search agent finds the flashlight as soon as it crosses the ray emanating from the flashlight, and in order to pick it up, the searcher has to move to the origin of the light beam. First, we give a search strategy for a special case of the ray(More)
The problem of localization, i.e. of a robot nding its position on a map, is an important task for autonomous mobile robots. It has applications in numerous areas of robotics ranging from aerial photography to autonomous vehicle exploration. In this paper we present a new strategy for a robot to nd its position on a map where the map is represented as a(More)
We define simple-regular expressions and languages. Simple-regular languages provide a necessary condition for a language to be outfix-free. We design algorithms that compute simple-regular languages from finite-state automata. Furthermore, we investigate the complexity blowup from a given finite-state automaton to its simple-regular language automaton and(More)
An influence factors analysis method for online auditing performance assessment based on AHP (analytic hierarchy process) and GIA (grey incidence analysis) is proposed in this paper according to the requirements of online auditing performance assessments. In this method, a grey incidence model is developed to analyze the influence factors of online auditing(More)
We report on two tests we performed in Hong Kong and Shanghai to verify the hypothesis that one can learn better when being given access to visualizations beyond the standard verbal explanations in a classroom. The outcome of the first test at HKUST was inconclusive, while the second test at Fudan University showed a clear advantage for those students who(More)