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Distribution-free factor analysis - Estimation theory and applicability to high-dimensional data [article]

Rolf Sundberg, Uwe Feldmann
2013 arXiv   pre-print
We here provide a distribution-free approach to the random factor analysis model. We show that it leads to the same estimating equations as for the classical ML estimates under normality, but more easily derived, and valid also in the case of more variables than observations (p>n). For this case we also advocate a simple iteration method. In an illustration with p=2000 and n=22 it was seen to lead to convergence after just a few iterations. We show that there is no reason to expect Heywood
more » ... to appear, and that the factor scores will typically be precisely estimated/predicted as soon as p is large. We state as a general conjecture that the nice behaviour is not despite p>n, but because p>n.
arXiv:1312.7439v1 fatcat:6kepccq57vbx5hsio2pwnddufa

Modelling and Discretization of Circuit Problems [chapter]

Michael Günther, Uwe Feldmann, Jan ter Maten
2005 Handbook of Numerical Analysis  
doi:10.1016/s1570-8659(04)13006-8 fatcat:h3l2jw323rbnbdz7y5wec3zitm

Grenzen und Herausforderungen der regionalen Klimamodellierung [chapter]

Andreas Dobler, Hendrik Feldmann, Uwe Ulbrich, Daniela Jacob, Christoph Kottmeier
2016 Klimawandel in Deutschland  
Regionale Simulationen verbessern besonders die Beschreibung der Niederschläge im Sommer, weil dann kleinskalige Vertikalbewegungen in der Atmosphäre die Niederschlagsbildung wesentlich beeinflussen (Feldmann  ... 
doi:10.1007/978-3-662-50397-3_5 fatcat:jrsf2k4subdyhit7tlp7wsbedi

Finding Beneficial DAE Structures in Circuit Simulation [chapter]

Roswitha März, Diana Estévez Schwarz, Uwe Feldmann, Sandra Sturtzel, Caren Tischendorf
2003 Mathematics — Key Technology for the Future  
Circuit simulation is a standard task for the computer{aided design of electronic circuits. The transient analysis is well understood and realized in powerful simulation packages for conventional circuits. But further developments in the production engineering lead to new classes of circuits which m a y cause di culties for the numerical integration. The dimension of circuit models can be quite large (10 5 equations). The complexity of the models demands a higher abstraction level. In this
more » ... , we analyze electric circuits with respect to their structural properties. We discuss the relevant subspaces of the resulting di erential algebraic equations (DAEs) and present algorithms for calculating the index as well as consistent initial values.
doi:10.1007/978-3-642-55753-8_34 fatcat:xe2pfkvb3ncitlxa6rh5wqx77u

Exploratory factor analysis—Parameter estimation and scores prediction with high-dimensional data

Rolf Sundberg, Uwe Feldmann
2016 Journal of Multivariate Analysis  
h i g h l i g h t s • We treat the case of more variables than observations (p > n) in the standard FA model. • For large p, factor scores can be estimated with high precision (n need not be large). • For large p, an old iteration method converges fast and with no inadmissible values. a b s t r a c t In an approach aiming at high-dimensional situations, we first introduce a distribution-free approach to parameter estimation in the standard random factor model, that is shown to lead to the same
more » ... stimating equations as maximum likelihood estimation under normality. The derivation is considerably simpler, and works equally well in the case of more variables than observations (p > n). We next concentrate on the latter case and show results of type: • Albeit factor loadings and specific variances cannot be precisely estimated unless n is large, this is not needed for the factor scores to be precise, but only that p is large; • A classical fixed point iteration method can be expected to converge safely and rapidly, provided p is large. A microarray data set, with p = 2000 and n = 22, is used to illustrate this theoretical result.
doi:10.1016/j.jmva.2016.02.013 fatcat:onux6lsiozhvxazj2oria6rrfe

Rapid Development of Composite Applications Using Annotated Web Services [chapter]

Lars Dannecker, Marius Feldmann, Tobias Nestler, Gerald Hübsch, Uwe Jugel, Klemens Muthmann
2010 Lecture Notes in Computer Science  
Developing service-based interactive applications is time consuming and nontrivial. Annotating web services with additional information about the user interface and behavior of the service promises to ease and accelerate the development process. In this paper we present a model-driven development approach that utilizes the advantages of annotated web services during the service composition. It enables a rapid development of simple service-based applications in a graphical manner. Besides the
more » ... cription of the process and the models, our current service composition tool implementation, the "ServFace Builder" is introduced. The ServFace Builder infers graphical UIs from functional interface descriptions such as WSDL files which then can be combined in a presentation-oriented way to a service-based interactive application.
doi:10.1007/978-3-642-16985-4_1 fatcat:75qhxacgjzhwnm254wpspaq7ee

An Integrated Approach for Creating Service-Based Interactive Applications [chapter]

Marius Feldmann, Jordan Janeiro, Tobias Nestler, Gerald Hübsch, Uwe Jugel, André Preussner, Alexander Schill
2009 Lecture Notes in Computer Science  
While the implementation of business logic and business processes based on service-oriented architectures is well-understood and covered by existing development approaches, integrated concepts that empower users to exploit the Internet of Services to create complex interactive applications are missing. In this paper, we present an integrated approach that fills this gap. Our approach builds upon service annotations that add meta-information related to user interface generation, service
more » ... ies, and service composition to existing service descriptions. Services can be composed visually to complex interactive applications based on these annotations without the need to write any code. The application code is generated completely from the service composition description. Our approach is able to support heterogeneous target environments ranging from client/server architectures to mobile platforms.
doi:10.1007/978-3-642-03658-3_105 fatcat:byintxqbyfbuzp4wl4b2eqlcfu

The ServFace Builder - A WYSIWYG Approach for Building Service-Based Applications [chapter]

Tobias Nestler, Marius Feldmann, Gerald Hübsch, André Preußner, Uwe Jugel
2010 Lecture Notes in Computer Science  
In this paper we present the ServFace Builder, an authoring tool that enables people without programming skills to design and create service-based interactive applications in a graphical manner. The tool exploits the concept of service annotations for developing multi-page interactive applications targeting various platforms and devices.
doi:10.1007/978-3-642-13911-6_37 fatcat:wltbhswyyvbqvb4uklyuxbmdgu

Model-based integration of genomics and metabolomics reveals SNP functionality in Mycobacterium tuberculosis [article]

Ove Oeyas, Sonia Borrel, Andrej Trauner, Michael Zimmermann, Julia Feldmann, Sebastien Gagneux, Joerg Stelling, Uwe Sauer, Mattia Zampieri
2019 bioRxiv   pre-print
Human tuberculosis is caused by members of the Mycobacterium tuberculosis complex (MTBC) and presents variable disease outcomes. The variation has primarily been attributed to host and environmental factors, but recent evidence indicates an additional role of genetic diversity among MTBC clinical strains. Here, we used metabolomics to unravel the potential role of genetic variations in conferring strain-specific adaptive capacity and vulnerability. To systematically identify functionality of
more » ... gle nucleotide polymorphisms (SNPs), we developed a constraint-based approach that integrates metabolomic and genomic data. Model-based predictions were systematically tested against independent metabolome data; they correctly classified SNP effects in pyruvate kinase and suggested a genetic basis for strain-specific sensitivity to the antibiotic para-aminosalicylic acid. Our method is broadly applicable to mutations in enzyme-encoding genes across microbial life, opening new possibilities for identifying strain-specific metabolic vulnerabilities that could lead to more selective treatment strategies.
doi:10.1101/555763 fatcat:jhfqyenmkvc6nctvk5pbb26u3u

Bright luminescence in lanthanide coordination polymers with tetrafluoroterephthalate as a bridging ligand

Miriam Sobieray, Jens Gode, Christiane Seidel, Marieke Poß, Claus Feldmann, Uwe Ruschewitz
2015 Dalton Transactions  
Ten lanthanide coordination polymers with tetrafluoroterephthalate as the linker were synthesized. Europium and terbium compounds exhibit intense red and green emission in the visible region with quantum yields up to 67%.
doi:10.1039/c4dt03733b pmid:25740408 fatcat:nthvb3emrfbfvcn4bx5jxg3dmq

Mutual validation of GNSS height measurements and high-precision geometric-astronomical leveling

Christian Hirt, Martin Schmitz, Uwe Feldmann-Westendorff, Gerhard Wübbena, Cord-Hinrich Jahn, Günter Seeber
2010 GPS Solutions  
and Jahn 2006; Featherstone 2008; Feldmann-Westendorff 2009) .  ...  In practice, an accuracy level of 1 cm and better for GNSSbased physical heights is often reached (Feldmann-Westendorff and Jahn 2006) .  ... 
doi:10.1007/s10291-010-0179-3 fatcat:nnopjiyt7redhppvoulxo6gul4

Compact Modeling of Injection Enhanced Insulated Gate Bipolar Transistor Valid for Optimization of Switching Frequency

Takao YAMAMOTO, Masataka MIYAKE, Uwe FELDMANN, Hans J^|^Uuml;RGEN MATTAUSCH, Mitiko MIURA-MATTAUSCH
2014 IEICE transactions on electronics  
doi:10.1587/transele.e97.c.1021 fatcat:w62gc6v5hjcu5ol5tiu66clzge

Cryogel-supported stem cell factory for customized sustained release of bispecific antibodies for cancer immunotherapy

Roberta Aliperta, Petra B. Welzel, Ralf Bergmann, Uwe Freudenberg, Nicole Berndt, Anja Feldmann, Claudia Arndt, Stefanie Koristka, Marcello Stanzione, Marc Cartellieri, Armin Ehninger, Gerhard Ehninger (+5 others)
2017 Scientific Reports  
Combining stem cells with biomaterial scaffolds provides a promising strategy for the development of drug delivery systems. Here we propose an innovative immunotherapeutic organoid by housing human mesenchymal stromal cells (MSCs), gene-modified for the secretion of an anti-CD33-anti-CD3 bispecific antibody (bsAb), in a small biocompatible star-shaped poly(ethylene glycol)-heparin cryogel scaffold as a transplantable and low invasive therapeutic machinery for the treatment of acute myeloid
more » ... mia (AML). The macroporous biohybrid cryogel platform displays effectiveness in supporting proliferation and survival of bsAb-releasing-MSCs overtime in vitro and in vivo, avoiding cell loss and ensuring a constant release of sustained and detectable levels of bsAb capable of triggering T-cell-mediated anti-tumor responses and a rapid regression of CD33 + AML blasts. This therapeutic device results as a promising and safe alternative to the continuous administration of short-lived immunoagents and paves the way for effective bsAb-based therapeutic strategies for future tumor treatments. Immunotherapy of tumors, i.e. harnessing the immune system for therapeutic benefit in cancer, has gained much prominence in the last years 1 . The main strategies are based on boosting the immune response via a plethora of compounds, such as antibodies, chemokines, vaccines or ex vivo stimulated immune effector cells 2 . However, for their wide-spread use several challenges with respect to pharmacokinetics, efficiency and safety still need to be met 3, 4 . Recent studies have demonstrated that combining cancer immunotherapy with biomaterials may help to address some of these limitations 3,5 . A wide variety of scaffolds and hydrogel-based platforms made of synthetic and natural materials, capable to modulate the immune response against tumors, have been described during the last decades 6 . For instance, biomaterials have been employed as devices for controlled delivery of active molecules and cells, or as engineered microenvironments for recruiting and programming immune cells in situ 3 . Here, we report an advanced approach for developing an immunotherapeutic organoid by housing human mesenchymal stromal cells (MSCs), genetically modified for the production of bispecific antibodies (bsAbs) in implantable, mechanically robust, sponge-like glycosaminoglycan (GAG)-based hydrogels (cryogels) 7-9 . The
doi:10.1038/srep42855 pmid:28205621 pmcid:PMC5311951 fatcat:wqfrqgynwbcdrnnl72jsvbf4qi

Utility of primary cells to examine NPC1 receptor expression in Mops condylurus, a potential Ebola virus reservoir

Marcel Bokelmann, Kathryn Edenborough, Nicole Hetzelt, Petra Kreher, Angelika Lander, Andreas Nitsche, Uwe Vogel, Heinz Feldmann, Emmanuel Couacy-Hymann, Andreas Kurth, Waleed Saleh Al-Salem
2020 PLoS Neglected Tropical Diseases  
Acknowledgments The authors are grateful to Friederike Feldmann and Elaine Haddock for technical assistance and to Joseph Prescott for copy-editing.  ... 
doi:10.1371/journal.pntd.0007952 pmid:31961874 pmcid:PMC6994141 fatcat:yvjxleso5rgt5duenx4fl5nyeq

Model-based integration of genomics and metabolomics reveals SNP functionality in Mycobacterium tuberculosis

Ove Øyås, Sonia Borrell, Andrej Trauner, Michael Zimmermann, Julia Feldmann, Thomas Liphardt, Sebastien Gagneux, Jörg Stelling, Uwe Sauer, Mattia Zampieri
2020 Proceedings of the National Academy of Sciences of the United States of America  
Human tuberculosis is caused by members of the Mycobacterium tuberculosis complex (MTBC) that vary in virulence and transmissibility. While genome-wide association studies have uncovered several mutations conferring drug resistance, much less is known about the factors underlying other bacterial phenotypes. Variation in the outcome of tuberculosis infection and diseases has been attributed primarily to patient and environmental factors, but recent evidence indicates an additional role for the
more » ... netic diversity among MTBC clinical strains. Here, we used metabolomics to unravel the effect of genetic variation on the strain-specific metabolic adaptive capacity and vulnerability. To define the functionality of single-nucleotide polymorphisms (SNPs) systematically, we developed a constraint-based approach that integrates metabolomic and genomic data. Our model-based predictions correctly classify SNP effects in pyruvate kinase and suggest a genetic basis for strain-specific inherent baseline susceptibility to the antibiotic para-aminosalicylic acid. Our method is broadly applicable across microbial life, opening possibilities for the development of more selective treatment strategies.
doi:10.1073/pnas.1915551117 pmid:32229570 fatcat:3ms32n436nfenfrep3vcb4nyja
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