Michael Kohnen

Learn More
OBJECTIVES To develop a general structure for semantic image analysis that is suitable for content-based image retrieval in medical applications and an architecture for its efficient implementation. METHODS Stepwise content analysis of medical images results in six layers of information modeling incorporating medical expert knowledge (raw data layer,(More)
The Kad network is a structured P2P network used for file sharing. Research has proved that Sybil and Eclipse attacks have been possible in it until recently. However, the past attacks are prohibited by newly implemented security measures in the client applications. We present a new attack concept which overcomes the countermeasures and prove its(More)
Automatic identification of frontal (posteroanterior/anteroposterior) vs. lateral chest radiographs is an important preprocessing step in computer-assisted diagnosis, content-based image retrieval, as well as picture archiving and communication systems. Here, a new approach is presented. After the radiographs are reduced substantially in size, several(More)
In the past few years, immense improvement was obtained in the field of content-based image retrieval (CBIR). Nevertheless, existing systems still fail when applied to medical image databases. Simple feature-extraction algorithms that operate on the entire image for characterization of color, texture, or shape cannot be related to the descriptive semantics(More)
Image retrieval in medical applications (IRMA) requires the cooperation of experts in the eld of medicine, image analysis, feature analysis and systems engineering. A distributed developing platform was implemented to support the progress of the IRMA{system. As the concept for this system strictly separates the steps for medical image retrieval, its(More)
Large efforts have been made for general applications of content-based image retrieval (CBIR). Established CBIR-systems globally evaluate color, texture, and also shape for retrieval. In medical imaging, local image characteristics are fundamental for image interpretation, which is based on a large amount of a-priori knowledge. Therefore, CBIR is rather(More)
  • L Schmöger, O O Versolato, M Schwarz, M Kohnen, A Windberger, B Piest +10 others
  • 2015
Control over the motional degrees of freedom of atoms, ions, and molecules in a field-free environment enables unrivalled measurement accuracies but has yet to be applied to highly charged ions (HCIs), which are of particular interest to future atomic clock designs and searches for physics beyond the Standard Model. Here, we report on the Coulomb(More)