Alexandrov T.,University of Bremen |
Alexandrov T.,Steinbeis Innovation Center |
Lasch P.,Robert Koch Institute RKI
Analytical Chemistry | Year: 2013
Over the past decade, confocal Raman microspectroscopic (CRM) imaging has matured into a useful analytical tool to obtain spatially resolved chemical information on the molecular composition of biological samples and has found its way into histopathology, cytology, and microbiology. A CRM imaging data set is a hyperspectral image in which Raman intensities are represented as a function of three coordinates: a spectral coordinate λ encoding the wavelength and two spatial coordinates x and y. Understanding CRM imaging data is challenging because of its complexity, size, and moderate signal-to-noise ratio. Spatial segmentation of CRM imaging data is a way to reveal regions of interest and is traditionally performed using nonsupervised clustering which relies on spectral domain-only information with the main drawback being the high sensitivity to noise. We present a new pipeline for spatial segmentation of CRM imaging data which combines preprocessing in the spectral and spatial domains with k-means clustering. Its core is the preprocessing routine in the spatial domain, edge-preserving denoising (EPD), which exploits the spatial relationships between Raman intensities acquired at neighboring pixels. Additionally, we propose to use both spatial correlation to identify Raman spectral features colocalized with defined spatial regions and confidence maps to assess the quality of spatial segmentation. For CRM data acquired from midsagittal Syrian hamster (Mesocricetus auratus) brain cryosections, we show how our pipeline benefits from the complex spatial-spectral relationships inherent in the CRM imaging data. EPD significantly improves the quality of spatial segmentation that allows us to extract the underlying structural and compositional information contained in the Raman microspectra. © 2013 American Chemical Society.
Sikora A.,Baden Wuerttemberg Cooperative State University Loerrach |
Lill D.,Steinbeis Innovation Center |
Schappacher M.,Steinbeis Innovation Center |
Gutjahr A.,Steinbeis Innovation Center
2011 11th International Conference on ITS Telecommunications, ITST 2011 | Year: 2011
In the research project Ko-TAG, which is part of the research initiative Ko-FAS, cooperative sensor technology is developed and its benefit for traffic safety applications is evaluated. As a result the new sensor concept shall provide essential input data for next generation driver assistant systems. A secondary radar principle based on communication signals enables localization of objects with simultaneous data transmission. It mainly concentrates on pedestrian and other vulnerable road user (VRU) detection, but also allows pre crash safety. This paper describes the elements of the system architecture, as well as the main characteristics of the communication protocols. These are designed to fulfil the functional requirements and to be compatible with existing protocols. With regard to the wireless link, the protocol is designed in such a way that it can be used as an extension to IEEE802.11p/WAVE protocol. With regard to the communication within the vehicle, an extension to the LocON-protocol is propped. The system is implemented in a hardware-software co-design approach. © 2011 IEEE.
Darriba D.,Heidelberg Institute for Theoretical Studies |
Weiss M.,University of Tübingen |
Weiss M.,Steinbeis Innovation Center |
Stamatakis A.,Heidelberg Institute for Theoretical Studies |
Stamatakis A.,Karlsruhe Institute of Technology
Bioinformatics | Year: 2016
Motivation: The presence of missing data in large-scale phylogenomic datasets has negative effects on the phylogenetic inference process. One effect that is caused by alignments with missing per-gene or per-partition sequences is that the inferred phylogenies may exhibit extremely long branch lengths. We investigate if statistically predicting missing sequences for organisms by using information from genes/partitions that have data for these organisms alleviates the problem and improves phylogenetic accuracy. Results: We present several algorithms for correcting excessively long branch lengths induced by missing data. We also present methods for predicting/imputing missing sequence data. We evaluate our algorithms by systematically removing sequence data from three empirical and 100 simulated alignments. We then compare the Maximum Likelihood trees inferred from the gappy alignments and on the alignments with predicted sequence data to the trees inferred from the original, complete datasets. The datasets with predicted sequences showed one to two orders of magnitude more accurate branch lengths compared to the branch lengths of the trees inferred from the alignments with missing data. However, prediction did not affect the RF distances between the trees. © The Author 2016. Published by Oxford University Press.
Sikora A.,Offenburg University of Applied Sciences |
Schappacher M.,Steinbeis Innovation Center
2013 International Conference on Connected Vehicles and Expo, ICCVE 2013 - Proceedings | Year: 2013
The IEEE802.11p standard describes a protocol for car-To-X and mainly for car-To-car-communication. It has found its place in hardware and firmware implementations and is currently tested in various field tests. In the research project Ko-TAG, which is part of the research initiative Ko-FAS, cooperative sensor technology is developed for the support of highly autonomous driving. A secondary radar principle based on communication signals enables localization of objects with simultaneous data transmission. It mainly concentrates on the detection of pedestrians and other vulnerable road users (VRU), but also supports pre crash safety applications. Thus it is mainly targeted for the support of traffic safety applications in intra-urban scenarios. This contribution describes the Ko-TAG part of the overall initiative, which develops a subsystem to improve the real-Time characteristics of IEEE802.11p needed for precise time of flight real-Time localization. In doing this, it still fits into the regulatory schemes. It discusses the approach for definition and verification of the protocol design, while maintaining the close coexistence with existing IEEE802.11p subsystems. System simulations were performed and hardware was implemented. Test results are shown in the last part of the paper. © 2013 IEEE.
Saleem A.,Zwickau University of Applied Sciences |
Frormann L.,Zwickau University of Applied Sciences |
Koltermann J.,Steinbeis Innovation Center |
Reichelt C.,Steinbeis Innovation Center
Journal of Applied Polymer Science | Year: 2014
The compounds of polypropylene (PP) with paraffin wax (PR) as phase change material were fabricated by extrusion melt compounding. The compounds of PR and PP were brittle and showed PR leakage within its melting point range. The maximum 60 weight percent content of the PR was compounded with the polymer. The high amount of paraffin in the polymer plasticized and significantly decreased the melting point of the polymer. The addition of a linear triblock copolymer based on styrene and ethylene/butylene noticeably ameliorated the workability, impact penetration and paraffin retention properties of the compounds. The compounds were further reinforced by carbon fibers and carbon nanotubes that led to an enhancement of their thermal conductivity and heat transfer efficiency. The material structure and thermophysical properties were studied by microscopy and various characterization techniques. The compounds of polymer with PR show phase change effect due to the solid-liquid phase transition of PR within its melting point range. The experimental time vs. temperature curves of the compounds were recorded within the melting range of PR. The experimental curves were compared with the theoretical calculated results. The results were in agreement except small difference that can be attributed to the experimental errors and the assumptions made during theoretical calculations. The manuscript describes the fabrication of shape enduring compounds, with improved thermal, physical, and mechanical properties and their processing by standard techniques, such as extrusion and blow molding. © 2013 Wiley Periodicals, Inc.