@article{ConradLeichtleNuofferetal.2012, author = {Conrad, Tim and Leichtle, Alexander Benedikt and Nuoffer, Jean-Marc and Ceglarek, Uta and Kase, Julia and Witzigmann, Helmut and Thiery, Joachim and Fiedler, Georg Martin}, title = {Serum amino acid profiles and their alterations in colorectal cancer}, journal = {Metabolomics}, doi = {10.1007/s11306-011-0357-5}, year = {2012}, abstract = {Mass spectrometry-based serum metabolic profiling is a promising tool to analyse complex cancer associated metabolic alterations, which may broaden our pathophysiological understanding of the disease and may function as a source of new cancer-associated biomarkers. Highly standardized serum samples of patients suffering from colon cancer (n = 59) and controls (n = 58) were collected at the University Hospital Leipzig. We based our investigations on amino acid screening profiles using electrospray tandem-mass spectrometry. Metabolic profiles were evaluated using the Analyst 1.4.2 software. General, comparative and equivalence statistics were performed by R 2.12.2. 11 out of 26 serum amino acid concentrations were significantly different between colorectal cancer patients and healthy controls. We found a model including CEA, glycine, and tyrosine as best discriminating and superior to CEA alone with an AUROC of 0.878 (95\\% CI 0.815?0.941). Our serum metabolic profiling in colon cancer revealed multiple significant disease-associated alterations in the amino acid profile with promising diagnostic power. Further large-scale studies are necessary to elucidate the potential of our model also to discriminate between cancer and potential differential diagnoses. In conclusion, serum glycine and tyrosine in combination with CEA are superior to CEA for the discrimination between colorectal cancer patients and controls.}, language = {en} } @article{ConradGenzelCvetkovicetal.2017, author = {Conrad, Tim and Genzel, Martin and Cvetkovic, Nada and Wulkow, Niklas and Leichtle, Alexander Benedikt and Vybiral, Jan and Kytyniok, Gitta and Sch{\"u}tte, Christof}, title = {Sparse Proteomics Analysis - a compressed sensing-based approach for feature selection and classification of high-dimensional proteomics mass spectrometry data}, volume = {18}, journal = {BMC Bioinfomatics}, number = {160}, doi = {10.1186/s12859-017-1565-4}, year = {2017}, abstract = {Background: High-throughput proteomics techniques, such as mass spectrometry (MS)-based approaches, produce very high-dimensional data-sets. In a clinical setting one is often interested in how mass spectra differ between patients of different classes, for example spectra from healthy patients vs. spectra from patients having a particular disease. Machine learning algorithms are needed to (a) identify these discriminating features and (b) classify unknown spectra based on this feature set. Since the acquired data is usually noisy, the algorithms should be robust against noise and outliers, while the identified feature set should be as small as possible. Results: We present a new algorithm, Sparse Proteomics Analysis (SPA),based on thet heory of compressed sensing that allows us to identify a minimal discriminating set of features from mass spectrometry data-sets. We show (1) how our method performs on artificial and real-world data-sets, (2) that its performance is competitive with standard (and widely used) algorithms for analyzing proteomics data, and (3) that it is robust against random and systematic noise. We further demonstrate the applicability of our algorithm to two previously published clinical data-sets.}, language = {en} } @article{WilsonAnglinAmbellanetal.2017, author = {Wilson, David and Anglin, Carolyn and Ambellan, Felix and Grewe, Carl Martin and Tack, Alexander and Lamecker, Hans and Dunbar, Michael and Zachow, Stefan}, title = {Validation of three-dimensional models of the distal femur created from surgical navigation point cloud data for intraoperative and postoperative analysis of total knee arthroplasty}, volume = {12}, journal = {International Journal of Computer Assisted Radiology and Surgery}, number = {12}, publisher = {Springer}, doi = {10.1007/s11548-017-1630-5}, pages = {2097 -- 2105}, year = {2017}, abstract = {Purpose: Despite the success of total knee arthroplasty there continues to be a significant proportion of patients who are dissatisfied. One explanation may be a shape mismatch between pre and post-operative distal femurs. The purpose of this study was to investigate a method to match a statistical shape model (SSM) to intra-operatively acquired point cloud data from a surgical navigation system, and to validate it against the pre-operative magnetic resonance imaging (MRI) data from the same patients. Methods: A total of 10 patients who underwent navigated total knee arthroplasty also had an MRI scan less than 2 months pre-operatively. The standard surgical protocol was followed which included partial digitization of the distal femur. Two different methods were employed to fit the SSM to the digitized point cloud data, based on (1) Iterative Closest Points (ICP) and (2) Gaussian Mixture Models (GMM). The available MRI data were manually segmented and the reconstructed three-dimensional surfaces used as ground truth against which the statistical shape model fit was compared. Results: For both approaches, the difference between the statistical shape model-generated femur and the surface generated from MRI segmentation averaged less than 1.7 mm, with maximum errors occurring in less clinically important areas. Conclusion: The results demonstrated good correspondence with the distal femoral morphology even in cases of sparse data sets. Application of this technique will allow for measurement of mismatch between pre and post-operative femurs retrospectively on any case done using the surgical navigation system and could be integrated into the surgical navigation unit to provide real-time feedback.}, language = {en} } @inproceedings{WeinholdLackorzynskiBierbaumetal.2016, author = {Weinhold, Carsten and Lackorzynski, Adam and Bierbaum, Jan and K{\"u}ttler, Martin and Planeta, Maksym and H{\"a}rtig, Hermann and Shiloh, Amnon and Levy, Ely and Ben-Nun, Tal and Barak, Amnon and Steinke, Thomas and Sch{\"u}tt, Thorsten and Fajerski, Jan and Reinefeld, Alexander and Lieber, Matthias and Nagel, Wolfgang}, title = {FFMK: A Fast and Fault-tolerant Microkernel-based System for Exascale Computing}, booktitle = {SPPEXA Symposium 2016}, doi = {10.1007/978-3-319-40528-5_18}, year = {2016}, language = {en} } @article{HeidaSikorskiWeber2022, author = {Heida, Martin and Sikorski, Alexander and Weber, Marcus}, title = {Consistency and order 1 convergence of cell-centered finite volume discretizations of degenerate elliptic problems in any space dimension}, journal = {SIAM Journal on Numerical Analysis}, doi = {10.20347/WIAS.PREPRINT.2913}, year = {2022}, abstract = {We study consistency of cell-centered finite difference methods for elliptic equations with degenerate coefficients in any space dimension \$d \geq 2\$. This results in order of convergence estimates in the natural weighted energy norm and in the weighted discrete \$L^2\$-norm on admissible meshes. The cells of meshes under consideration may be very irregular in size. We particularly allow the size of certain cells to remain bounded from below even in the asymptotic limit. For uniform meshes we show that the order of convergence is at least 1 in the energy semi-norm, provided the discrete and continuous solutions exist and the continuous solution has \$H^2\$ regularity.}, language = {en} } @article{SikorskiHeida2024, author = {Sikorski, Alexander and Heida, Martin}, title = {Voronoi Graph - Improved raycasting and integration schemes for high dimensional Voronoi diagrams}, arxiv = {http://arxiv.org/abs/2405.10050}, year = {2024}, abstract = {The computation of Voronoi Diagrams, or their dual Delauney triangulations is difficult in high dimensions. In a recent publication Polianskii and Pokorny propose an iterative randomized algorithm facilitating the approximation of Voronoi tesselations in high dimensions. In this paper, we provide an improved vertex search method that is not only exact but even faster than the bisection method that was previously recommended. Building on this we also provide a depth-first graph-traversal algorithm which allows us to compute the entire Voronoi diagram. This enables us to compare the outcomes with those of classical algorithms like qHull, which we either match or marginally beat in terms of computation time. We furthermore show how the raycasting algorithm naturally lends to a Monte Carlo approximation for the volume and boundary integrals of the Voronoi cells, both of which are of importance for finite Volume methods. We compare the Monte-Carlo methods to the exact polygonal integration, as well as a hybrid approximation scheme.}, language = {en} } @article{XieGruberCrampenetal.2025, author = {Xie, Kunpeng and Gruber, Lennart Johannes and Crampen, Martin and Li, Yao and Ferreira, Andr{\´e} and Tappeiner, Elias and Gillot, Maxime and Schepers, Jan and Xu, Jiangchang and Pankert, Tobias and Beyer, Michel and Shahamiri, Negar and ten Brink, Reinier and Dot, Gauthier and Weschke, Charlotte and van Nistelrooij, Niels and Verhelst, Pieter-Jan and Guo, Yan and Xu, Zhibin and Bienzeisler, Jonas and Rashad, Ashkan and Fl{\"u}gge, Tabea and Cotton, Ross and Vinayahalingam, Shankeeth and Ilesan, Robert and Raith, Stefan and Madsen, Dennis and Seibold, Constantin and Xi, Tong and Berg{\´e}, Stefaan and Nebelung, Sven and Kodym, Oldřich and Sundqvist, Osku and Thieringer, Florian and Lamecker, Hans and Coppens, Antoine and Potrusil, Thomas and Kraeima, Joep and Witjes, Max and Wu, Guomin and Chen, Xiaojun and Lambrechts, Adriaan and Cevidanes, Lucia H Soares and Zachow, Stefan and Hermans, Alexander and Truhn, Daniel and Alves, Victor and Egger, Jan and R{\"o}hrig, Rainer and H{\"o}lzle, Frank and Puladi, Behrus}, title = {Beyond Benchmarks: Towards Robust Artificial Intelligence Bone Segmentation in Socio-Technical Systems}, volume = {299}, journal = {Expert Systems With Applications}, number = {Part D}, doi = {10.1016/j.eswa.2025.130031}, year = {2025}, abstract = {Despite the advances in automated medical image segmentation, AI models still underperform in various clinical settings, challenging real-world integration. In this multicenter evaluation, we analyzed 20 state-of-the-art mandibular segmentation models across 19,218 segmentations of 1,000 clinically resampled CT/CBCT scans. We show that segmentation accuracy varies by up to 25\% depending on socio-technical factors such as voxel size, bone orientation, and patient conditions such as osteosynthesis or pathology. Higher sharpness, isotropic smaller voxels, and neutral orientation significantly improved results, while metallic osteosynthesis and anatomical complexity led to significant degradation. Our findings challenge the common view of AI models as "plug-and-play" tools and suggest evidence-based optimization recommendations for both clinicians and developers. This will in turn boost the integration of AI segmentation tools in routine healthcare.}, language = {en} } @article{BaermannMartinPokuttaetal.2018, author = {B{\"a}rmann, Andreas and Martin, Alexander and Pokutta, Sebastian and Schneider, Oskar}, title = {An Online-Learning Approach to Inverse Optimization}, year = {2018}, language = {en} } @article{EisenblaetterGeerdesKochetal.2005, author = {Eisenbl{\"a}tter, Andreas and Geerdes, Hans-Florian and Koch, Thorsten and Martin, Alexander and Wess{\"a}ly, Roland}, title = {UMTS Radio Network Evaluation and Optimization beyond Snapshots}, volume = {63}, journal = {Mathematical Methods of Operations Research}, number = {1}, doi = {10.1007/s00186-005-0002-z}, pages = {1 -- 29}, year = {2005}, language = {en} } @inproceedings{FuegenschuhHessMartinetal.2007, author = {F{\"u}genschuh, Armin and Hess, Wolfgang and Martin, Alexander and Ulbrich, Stefan}, title = {Diskrete und kontinuierliche Modelle zur Topologie- und Geometrie-Optimierung von Blechprofilen}, booktitle = {Sonderforschungsbereich 666}, editor = {Groche, P.}, pages = {37 -- 47}, year = {2007}, language = {en} } @book{GroetschelLovaszSchrijver1993, author = {Gr{\"o}tschel, Martin and Lov{\´a}sz, L{\´a}szlo and Schrijver, Alexander}, title = {Geometric Algorithms and Combinatorial Optimization}, volume = {2}, journal = {Algorithms and Combinatorics}, edition = {Second corrected edition}, publisher = {Springer}, isbn = {3-540-56740-2, 0-387-56740-2 (U.S.)}, year = {1993}, language = {en} } @incollection{EisenblaetterFuegenschuhKochetal.2002, author = {Eisenbl{\"a}tter, Andreas and F{\"u}genschuh, Armin and Koch, Thorsten and Koster, Arie M.C.A. and Martin, Alexander and Pfender, Tobias and Wegel, Oliver and Wess{\"a}ly, Roland}, title = {Mathematical Model of Feasible Network Configurations for UMTS}, booktitle = {Telecommunications network design and management}, editor = {G. Anandalingam, S.}, publisher = {Kluwer}, pages = {1 -- 24}, year = {2002}, language = {en} } @inproceedings{FuegenschuhMartinStoeveken2004, author = {F{\"u}genschuh, Armin and Martin, Alexander and St{\"o}veken, Peter}, title = {Integrated Optimization of School Starting Times and Public Bus Services}, booktitle = {Mathematics in the Supply Chain}, editor = {Bixby, Robert E. and Simchi-Levi, D. and Martin, Alexander and Zimmermann, U.}, year = {2004}, language = {en} } @inproceedings{EisenblaetterFuegenschuhGeerdesetal.2004, author = {Eisenbl{\"a}tter, Andreas and F{\"u}genschuh, Armin and Geerdes, Hans-Florian and Junglas, Daniel and Koch, Thorsten and Martin, Alexander}, title = {Integer Programming Methods for UMTS Radio Network Planning}, booktitle = {Proceedings of the WiOpt'04, Cambridge, UK}, year = {2004}, language = {en} } @incollection{FuegenschuhMartin2005, author = {F{\"u}genschuh, Armin and Martin, Alexander}, title = {Computational Integer Programming and Cutting Planes}, booktitle = {Handbooks in Operations Research and Management Science, Vol. 12}, editor = {Aardal, Karen I. and Nemhauser, George and Weismantel, R.}, publisher = {North-Holland}, pages = {69 -- 122}, year = {2005}, language = {en} } @inproceedings{FuegenschuhHomfeldHucketal.2006, author = {F{\"u}genschuh, Armin and Homfeld, Henning and Huck, Andreas and Martin, Alexander}, title = {Locomotive and Wagon Scheduling in Freight Transport}, booktitle = {Proceedings of the ATMOS06}, editor = {Jacob, R. and M{\"u}ller-Hannemann, Matthias}, year = {2006}, language = {en} } @inproceedings{FuegenschuhMartinMehlertetal.2005, author = {F{\"u}genschuh, Armin and Martin, Alexander and Mehlert, Christian and St{\"o}veken, Peter}, title = {Ein Planungstool zur Schulzeitstaffelung}, booktitle = {Supply Chain Management und Logistik}, editor = {G{\"u}nther, H.-O. and Mattfeld, D. and Suhl, L.}, pages = {419 -- 436}, year = {2005}, language = {en} } @inproceedings{FuegenschuhMartinStoeveken2005, author = {F{\"u}genschuh, Armin and Martin, Alexander and St{\"o}veken, Peter}, title = {Integrated Optimization of School Starting Times and Public Bus Services}, booktitle = {Operations Research Proceedings}, editor = {Fleuren, Hein and den Hertog, Dick and Kort, Peter}, pages = {150 -- 157}, year = {2005}, language = {en} } @inproceedings{FuegenschuhMartin2007, author = {F{\"u}genschuh, Armin and Martin, Alexander}, title = {Mixed-integer models for topology optimization in sheet metal design}, booktitle = {Sixth International Congress on Industrial Applied Mathematics (ICIAM07) and GAMM Annual Meeting, Z{\"u}rich 2007}, pages = {2060049 -- 2060050}, year = {2007}, language = {en} } @inproceedings{FuegenschuhlerMartinetal.2009, author = {F{\"u}genschuh, Armin and ler, Bj{\"o}rn and Martin, Alexander and Morsi, Antonio}, title = {The Transport PDE and Mixed-Integer Linear Programming}, booktitle = {Dagstuhl Seminar Proceedings 09261, Schloss Dagstuhl - Leibniz-Zentrum f{\"u}r Informatik, Deutschland}, editor = {Barnhart, Cynthia and Clausen, Uwe and Lauther, Ulrich and M{\"o}hring, Rolf}, year = {2009}, language = {en} } @inproceedings{FuegenschuhHessScheweetal.2008, author = {F{\"u}genschuh, Armin and Hess, Wolfgang and Schewe, Lars and Martin, Alexander and Ulbrich, Stefan}, title = {Verfeinerte Modelle zur Topologie- und Geometrie-Optimierung von Blechprofilen mit Kammern}, booktitle = {Sonderforschungsbereich 666}, editor = {Groche, P.}, pages = {17 -- 28}, year = {2008}, language = {en} } @incollection{BorndoerferHoangKarbsteinetal.2013, author = {Bornd{\"o}rfer, Ralf and Hoang, Nam-Dung and Karbstein, Marika and Koch, Thorsten and Martin, Alexander}, title = {How many Steiner terminals can you connect in 20 years?}, booktitle = {Facets of Combinatorial Optimization; Festschrift for Martin Gr{\"o}tschel}, editor = {J{\"u}nger, Michael and Reinelt, Gerhard}, publisher = {Springer}, doi = {10.1007/978-3-642-38189-8_10}, pages = {215 -- 244}, year = {2013}, language = {en} }