Van Huffel Research Articles

“First Woman to…” Exceptionalism Discourse

“First women to…” labels define the ways in which women leaders are characterized as “exceptional”. As already pointed out by some feminist scholars, exceptionalism discourse valorizes women’s achievements to the benefit of institutions and their patriarchal culture. While such valorization might enhance gender representation in spaces previously reserved for men, it also commodifies women’s capabilities. This, I argue, calls for resisting the subtle, less visible, often unintentional, and sometimes patronizing forms of discrimination that sustain the patriarchal culture of institutions such as “the church”. Many feminist theologians have repeatedly named “the cultural-political power at work in our world as patriarchy”. Questions about the relationship between patriarchal institutional culture and the legitimate presence of women leaders are central to the argument presented here. The case of South African feminist theologian, Mary-Anne Plaatjies Van Huffel, is used to illustrate the relentless task women face of having to challenge pervasive gender-bias in the patriarchal institutional culture of the church. I then explore the plausibility of reflective solidarity as a theo-ethical concept and its potential to transform the patriarchal institutional culture of the church.

Unidentifiability of errors-in-variables models with rank deficiency from measurements

Although errors-in-variables (EIV) models have been substantially investigated, rank deficient EIV models have not been properly addressed. This paper proves the following major results: (i) given a full EIV model that the elements of its coefficient matrix are continuous random variables with a positive definite variance–covariance matrix, such an EIV model cannot be rank deficient with probability one, indicating that the non-uniqueness condition of total least squares solutions by Golub and van Loan [1] and van Huffel and Vandewalle [2, 3] cannot be true with probability one; (ii) even if a full EIV model is theoretically rank deficient, its rank deficiency cannot be identifiable from measurements with probability one. A full EIV model with theoretical rank deficiency can almost always be incorrectly identified to be an estimable model with probability one, due to the randomness of the coefficient matrix; and (iii) if an EIV model is rank deficient, it must be a partial EIV model, though a partial EIV model is not necessarily rank deficient. Further, if a partial EIV model is rank deficient, we may not numerically obtain its exact rank. These theoretical results have a practical engineering implication that solutions to a rank deficient EIV model from random measurements can be totally incorrect without the notice of an engineer, since there exist an infinite number of mathematically equivalent solutions to such an EIV model. We propose two methods to solve a partial rank deficient EIV model for a unique solution by imposing extra subjective information.

Born into a World of Hostility and Contradiction: The Role of Mary-Anne Elizabeth Plaatjies-Van Huffel in URCSA

Prof. Dr Mary-Anne Plaatjies van Huffel was born, bred and ordained as a minister of the word and sacraments in a notoriously patriarchal society. Besides the racial yoke of apartheid in the country of her birth, she also had to carry the burden of sexism, misogyny, machismo and marianismo in her daily life. Without compromise, but with a deep sense of gentleness, boldness and respect, she confronted and spoke truth to those who held important leadership positions. Prof. Dr Mary-Anne Plaatjies van Huffel demanded a moral response from church leadership to the oppression of women in the church instead of an expedient, easy or selfish response. She was the first woman to be ordained in and appointed to the leadership of the church after a long wait for ordination. Her confrontation of patriarchy and its surrogates carried a connotation of bravery, and of risk to her career, reputation and livelihood. After her admission to the full ministry of the church, she climbed the ranks both as a church leader both locally and internationally. This article articulates Prof. Dr Mary-Anne Plaatjies van Huffel’s work, role and contribution in her ministry in the Uniting Reformed Church in Southern Africa and in the ecumenical movement until her untimely death on 19 May 2020.

Integrating old and new complexity measures toward automated seizure detection from long-term video EEG recordings

SummaryAutomated seizure detection in long-term video-EEG recordings is far from being integrated into common clinical practice. Here, we leverage classical and state-of-the-art complexity measures to robustly and automatically detect seizures from scalp recordings. Brain activity is scored through eight features, encompassing traditional time domain and novel measures of recurrence. A binary classification algorithm tailored to treat unbalanced dataset is used to determine whether a time window is ictal or non-ictal from its features. The application of the algorithm on a cohort of ten adult patients with focal refractory epilepsy indicates sensitivity, specificity, and accuracy of 90%, along with a true alarm rate of 95% and less than four false alarms per day. The proposed approach emphasizes ictal patterns against noisy background without the need of data preprocessing. Finally, we benchmark our approach against previous studies on two publicly available datasets, demonstrating the good performance of our algorithm.

Tribute to Rev. Prof. Dr Mary‐Anne Plaatjies van Huffel, World Council of Churches president from Africa

Tribute to Rev. Prof. Dr Mary‐Anne Plaatjies van Huffel, World Council of Churches president from Africa

Investigating Driver Sympathetic Arousal under Short-term Loads and Acute Stress Events

This study involved an investigation of patterns of arousal in a driver’s sympathetic nervous system toward a system that can detect high cognitive workload, high emotional load, and acute stress (surprise or panic) experiences in drivers. Humans are exposed to cognitive and physical stressors in the driving environment that can be exacerbated when drivers are operating under the cognitive effects of incidental emotions or secondary task loads. Each type of stressor can negatively affect the control of complex operational systems, such as a vehicle, in different ways. The body’s sympathetic autonomous nervous system (the “fight or flight” system) triggers several physiological changes in the body, such as perspiratory and cardiac dynamics, in order to prepare the human to defend themselves or run away. Physiological sensor systems can therefore be used to collect data on these physiological changes (such as heart rate variability (HRV; Taelman, Vandeput, Spaopon, & Van Huffel, 2009) and skin conductance response (SCR; Boucsein, 2012; Shi, Ruiz, Taib, Choi, & Chen, 2007; Villarejo, Zapirain, & Zorrilla, 2012). Data processing techniques can be applied to identify patterns in physiological response across multiple variables and time windows that are characteristics of potentially problematic driver mental states. As a first step toward developing an online system for detecting potentially-problematic driver mental states, this study sought to identify patterns in HRV and SCR data associated with each of these states, and to investigate the predictive power of such an algorithm for explaining aspects of driving behavior. Eighty-eight people (with equal representation from each sex and each of two age groups) participated in a driving simulator study. The simulation scenarios consisted of a simulated rural highway with multiple predetermined segments where secondary task loads were applied. After a physiological baselining procedure and adequate practice with the driving and secondary tasks, participants completed scenarios under each of the six driving conditions: a “Normal” drive with a simple roadway and no secondary tasks, four “Loaded” drives that included driving-related loads (e.g., construction zones) and some additional secondary tasks designed to impose analytical cognitive, emotional, and motoric (e.g., texting task) loads. A final scenario included varied combinations of these loads and a unique surprising “Failure” event (triggered acceleration in the vehicle that mimicked unintended acceleration problems). HRV and SCR were measured throughout the experiment using Zephyr Bioharness3 and Shimmer3 sensor systems, respectively, and numerous third-party software packages were used to process the data and identify noteworthy patterns. This presentation will report the analytical results of three dependent variables: HRV, SCR-amplitude (i.e., the magnitude of characteristic increases in arousal during sympathetic response), and SCR-frequency (i.e., the frequency of skin conductance responses identified within a predetermined time window). HRV (measured over time windows of a few seconds, as well as of several minutes) and SCR-Frequency were significantly sensitive to changes in loading, and some patterns in dynamics among multiple measures can be used to differentiate the designed mental states, although further testing is underway to refine and validate these findings. In particular, SCR- amplitude may be an effective way to distinguish acute stress events, as this measure shows a significant and substantial change within 2.5 seconds after realization of the unintended acceleration event. In addition to discussing these results, the current and future efforts in the development of an online driver “stressor detector” and mitigation system will be introduced in the presentation as well.

Abstract 4518: 4CSeq analysis of a breast cancer susceptibility locus on 6q25.1

Abstract Single nucleotide polymorphisms within the genomic region immediately upstream of ESR1, a gene on 6q25.1 encoding the estrogen receptor α (ER), have been found to be associated with increased risk of breast cancer1,2. Three genes within this region, CCDC170, RMND1 and ARMT1 are co-expressed with ESR1 in ER+ve breast cancers and CCDC170 expression is inversely associated with proliferation and recurrence free survival in a tamoxifen-treated patient cohort3. In addition, gene fusions between ESR1 and CCDC170 have been associated with aggressive and endocrine-resistant luminal B tumours4. This study aimed to investigate chromatin structure within the 6q25.1 region using targeted chromatin confirmation capture (3C) and circularised chromatin confirmation capture analysis sequencing (4Cseq) to explore whether the spatial organisation of the chromatin might be associated with the regulation of genes and mutational patterns at this locus. To carry out 4Cseq analysis, chromatin from MCF7 cells was cross-linked, enzymatically digested, ligated, re-digested, circularised and then amplified before the purified PCR products were sequenced on an Illumina HiSeq2500. After the sequence reads were trimmed and processed, FourSig software was used to identify cis and trans interactions from the nine anchor points used in the assay. For 3C analysis, chromatin was cross-linked, digested, ligated, and analysed by quantitative real-time PCR. Data was normalised to a synthetically generated fragment. Analyses revealed that the ESR1 promoter region contacted a number of different upstream regions including the promoters of RMND1 and CCDC170. A high frequency of interactions was observed in the intergenic region between CCDC170 and ESR1 where a number of SNPs associated with breast cancer risk have been found. In addition, contact between the 3’ end of the ESR1 gene and the 3’ end of CCDC170 suggests that there may be a regulatory interaction in this region. Contacts were also observed within CCDC170, immediately adjacent to the point at which gene fusions between ESR1 and CCDC170 have previously been observed4. Overall, these data support the hypothesis that chromatin structure may drive the co-expression of the genes at this locus and suggests that some interactions within the region occur in areas where genomic rearrangements in metastatic breast cancers have been observed.

National summary reports on pesticide residue analysis performed in 2013

EFSA Supporting PublicationsVolume 12, Issue 3 755E Technical reportOpen Access National summary reports on pesticide residue analysis performed in 2013 European Food Safety Authority (EFSA), European Food Safety Authority (EFSA)Search for more papers by this author European Food Safety Authority (EFSA), European Food Safety Authority (EFSA)Search for more papers by this author First published: 12 March 2015 https://doi.org/10.2903/sp.efsa.2015.EN-755 Published date: 12 March 2015 Question number: EFSA-Q-2015-00057 AboutPDF ToolsExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL References EFSA (European Food Safety Authority) 2014. Use of the EFSA Standard Sample Description for the reporting of data on the control of pesticide residues in food and feed according to Regulation (EC) No 396/2005 (2013 Data Collection). EFSA Journal 2014; 12(1):3545, 60 pp. doi:10.2903/j.efsa.2014.3545 EFSA (European Food Safety), 2015. The 2013 European Union report on pesticide residues in food. EFSA Journal 2015; 13(3):4038, 170 pp. doi:10.2903/j.efsa.2015.4038 EU (European Commission), 2004. Notification criteria for pesticide residue findings to the Rapid Alert System for Food and Feed. SANCO/3346/2001, revision 7. EU (European Commission), 2009. Method Validation and Quality Control Procedures for Pesticide Residues Analysis in Food and Feed. SANCO/10684/2009. EU (European Commission), 2011. Method Validation and Quality Control Procedures for Pesticide Residues Analysis in Food and Feed. SANCO/12495/2011. ISO/IEC (International Organization for Standardization and the International Electro-technical Commission), 2010. General requirements for the competence of testing and calibration laboratories. 17025:2005, 28p. Maudoux J-P, Saegerman C, Rettigner C, Houins G, van Huffel X and Berkvens D, 2006. Food safety surveillance by a risk based control programming: approach applied by the Belgian federal agency for the safety of the food chain. Veterinary Quarterly, 28(4), 140– 154. Petersen A, Hamborg B, Andersen J H, Poulsen M E, Christensen T, Nielsen E, 2013. Pesticides residues, results from the period 2004–2011. ISBN 978-87-92763-78-5. The Netherlands' General Inspectorate for Health Protection, Ministry of Public Health, Welfare and Sports, 1996. Analytical Methods for Pesticide Residues in Foodstuffs. 6th Ed. Volume12, Issue3March 2015755E ReferencesRelatedInformation

National summary reports on pesticide residue analysis performed in 2012

EFSA Supporting PublicationsVolume 11, Issue 12 700E Technical reportOpen Access National summary reports on pesticide residue analysis performed in 2012 European Food Safety Authority (EFSA), European Food Safety Authority (EFSA)Search for more papers by this author European Food Safety Authority (EFSA), European Food Safety Authority (EFSA)Search for more papers by this author First published: 11 December 2014 https://doi.org/10.2903/sp.efsa.2014.EN-700 Published date: 11 December 2014 Question number: EFSA-Q-2014-00835 AboutPDF ToolsExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat References EFSA (European Food Safety Authority), 2013. Use of the EFSA Standard Sample Description for the reporting of data on the control of pesticide residues in food and feed according to Regulation (EC) No 396/2005 (Revision 2). EFSA Journal 2013; 11(1):3076, 54 pp. doi:10.2903/j.efsa.2013.3076. EFSA (European Food Safety Authority), 2014. The 2012 European Union Report on Pesticide Residues in Food. EFSA Journal 2014 – to be completed. EU (European Commission), 2004. Notification criteria for pesticide residue findings to the Rapid Alert System for Food and Feed. SANCO/3346/2001, revision 7. EU (European Commission), 2009. Method Validation and Quality Control Procedures for Pesticide Residues Analysis in Food and Feed. SANCO/10684/2009. EU (European Commission), 2011. Method Validation and Quality Control Procedures for Pesticide Residues Analysis in Food and Feed. SANCO/12495/2011. ISO/IEC (International Organization for Standardization and the International Electro-technical Commission), 2010. General requirements for the competence of testing and calibration laboratories. 17025:2005, 28p. Maudoux J-P, Saegerman C, Rettigner C, Houins G, van Huffel X and Berkvens D, 2006. Food safety surveillance by a risk based control programming: approach applied by the Belgian federal agency for the safety of the food chain. Veterinary Quarterly, 28(4), 140– 154. The Netherlands' General Inspectorate for Health Protection, Ministry of Public Health, Welfare and Sports, 1996. Analytical Methods for Pesticide Residues in Foodstuffs. 6th Ed. Petersen A, Hamborg B, Andersen J H, Poulsen M E, Christensen T, Nielsen E, 2013. Pesticides residues, results from the period 2004–2011. ISBN 978-87-92763-78–5. Volume11, Issue12December 2014700E ReferencesRelatedInformation

Abstract 403: Expression of genes spanning a breast cancer susceptibility locus on 6q25.1 is modulated by epigenetic modification

Abstract Single nucleotide polymorphisms within the region immediately upstream of the gene encoding ERα (ESR1) on 6q25.1, have been found to be associated with increased risk of breast cancer1,2. Three genes within this region, CCDC170, RMND1 and C6ORF211 are co-expressed with ESR1 in oestrogen receptor positive (ER+ve) breast cancers and CCDC170 expression is inversely associated with proliferation and recurrence free survival in a tamoxifen-treated patient cohort3. Epigenetic modification represents one potential mechanism through which expression of co-localised genes could be modulated. We investigated methylation and chromatin structure in the 6q25.1 using methylation sensitive sequencing, chromatin immunoprecipitation (ChIP) and chromatin confirmation capture (3C). Gene expression of ESR1, the three genes and alternative ESR1 mRNA isoforms were analysed in vitro using a panel of breast cancer cell lines. Long-term oestrogen deprived (LTED) cell lines were also generated and used to model the effects of anti-oestrogen therapies used in the treatment of ER positive breast cancers. DNA methylation at the ESR1/CCDC170 locus, gene expression of the four transcripts and alternative ESR1 mRNA isoforms differed greatly between the breast cancer cell lines. ER negative breast cancer cell lines were similar to the ‘non-tumorigenic’ MCF10A cell line while ER positive cell lines were hypomethylated and showed higher expression relative to MCF10A. We also discovered two putative regulatory binding regions which were differentially methylated that correlated with gene expression in our cell lines; one negatively and one positively. Analysis of ER positive tumors found that oestrogen receptor positive tumors were hypomethylated relative to normal tissue. In tumors, two differentially methylated regions were shown to have a strong negative correlation with gene expression of ESR1 and the three genes. These gave correlation coefficients of -0.577, -0.593, -0.600 and -0.454 for ESR1, CCDC170, C6ORF211 and RMND1, respectively, using Pearson correlation analysis and correction for multiple testing. The differentially methylated regions in tumors coincided with binding sites for ERα and Cohesin and long range chromatin interaction sites involving RNA polymerase II. Therefore, reduced DNA methylation seen in the ER positive tumors could facilitate enhanced chromatin interactions and transcription leading to the co-expression of the transcriptional hub. These alterations seen in the 6q25.1 locus, both in vitro and in our dataset, distinguish ER positive tumors and may contribute to resistance to anti-oestrogen therapies.

Early pregnancy failure: beware of the pitfalls of modern management

The evolution of the diagnosis and management of women with an early pregnancy loss has been a success story. The mortality from ectopic pregnancy has objectively been decreased in the past few decades. However, modern management has resulted in a new set of issues. Over-interpretation of a single ultrasound, misunderstanding of the utility of serial hCG values, and inappropriate use of methotrexate can result in iatrogenic complications. Modern management has successfully improved the diagnosis of ectopic pregnancy before rupture; it should now also focus on ensuring that an intrauterine pregnancy is not interrupted as a result of diagnosis and treatment. This article reviews some of the pitfalls of the modern management of early pregnancy failure and introduces a series of articles on the subject.

The Total Least Squares Problem in AX≈B: A New Classification with the Relationship to the Classical Works

This paper revisits the analysis of the total least squares (TLS) problem AX≈B with multiple right-hand sides given by Van Huffel and Vandewalle in the monograph, The Total Least Squares Problem: Computational Aspects and Analysis, SIAM, Philadelphia, 1991. The newly proposed classification is based on properties of the singular value decomposition of the extended matrix [B|A]. It aims at identifying the cases when a TLS solution does or does not exist and when the output computed by the classical TLS algorithm, given by Van Huffel and Vandewalle, is actually a TLS solution. The presented results on existence and uniqueness of the TLS solution reveal subtleties that were not captured in the known literature.

Host Defenses Trigger Salmonella 's Arsenal

Salmonella survives in macrophages by using a molecular syringe to deliver proteins into the host-cell cytosol where they manipulate phagocyte physiology. Arpaia and colleagues (Arpaia etal., 2011) show that deployment of this virulence factor is triggered by the very responses that are intended to confer host resistance.

The RNA Binding Motif Protein 15B (RBM15B/OTT3) Is a Functional Competitor of Serine-Arginine (SR) Proteins and Antagonizes the Positive Effect of the CDK11p110-Cyclin L2α Complex on Splicing

Here, we report the identification of the RNA binding motif protein RBM15B/OTT3 as a new CDK11(p110) binding partner that alters the effects of CDK11 on splicing. RBM15B was initially identified as a binding partner of the Epstein-Barr virus mRNA export factor and, more recently, as a cofactor of the nuclear export receptor NXF1. In this study, we found that RBM15B co-elutes with CDK11(p110), cyclin L2α, and serine-arginine (SR) proteins, including SF2/ASF, in a large nuclear complex of ∼1-MDa molecular mass following size exclusion chromatography. Using co-immunoprecipitation experiments and in vitro pulldown assays, we mapped two distinct domains of RBM15B that are essential for its direct interaction with the N-terminal extension of CDK11(p110), cyclin L2α, and SR proteins such as 9G8 and SF2/ASF. Finally, we established that RBM15B is a functional competitor of the SR proteins SF2/ASF and 9G8, inhibits formation of the functional spliceosomal E complex, and antagonizes the positive effect of the CDK11(p110)-cyclin L2α complex on splicing both in vitro and in vivo.

A Contribution to the Conditioning of the Total Least-Squares Problem

We derive closed formulas for the condition number of a linear function of the total least-squares solution. Given an overdetermined linear system Ax≈b, we show that this condition number can be computed using the singular values and the right singular vectors of [A,b] and A. We also provide an upper bound that requires the computation of the largest and the smallest singular value of [A,b] and the smallest singular value of A. In numerical examples, we compare these values and the resulting forward error bounds with the error estimates given by Van Huffel and Vandewalle [The Total Least Squares Problem: Computational Aspects and Analysis, Frontiers Appl. Math. 9, SIAM, Philadelphia, 1991], and we show the limitation of the first order approach.

Quantitative Proteomics Analysis of Macrophage Rafts Reveals Compartmentalized Activation of the Proteasome and of Proteasome-mediated ERK Activation in Response to Lipopolysaccharide

Lipopolysaccharide (LPS), a glycolipid component of the outer membrane of Gram-negative bacteria, is a potent initiator of the innate immune response of the macrophage. LPS triggers downstream signaling by selectively recruiting and activating proteins in cholesterol-rich membrane microdomains called lipid rafts. We applied proteomics analysis to macrophage detergent-resistant membranes (DRMs) during an LPS exposure time course in an effort to identify and validate novel events occurring in macrophage rafts. Following metabolic incorporation in cell culture of heavy isotopes of amino acids arginine and lysine ([(13)C(6)]Arg and [(13)C(6)]Lys) or their light counterparts, a SILAC (stable isotope labeling with amino acids in cell culture)-based quantitative, liquid chromatography-tandem mass spectrometry proteomics approach was used to profile LPS-induced changes in the lipid raft proteome of RAW 264.7 macrophages. Unsupervised network analysis of the proteomics data set revealed a marked representation of the ubiquitin-proteasome system as well as changes in proteasome subunit composition following LPS challenge. Functional analysis of DRMs confirmed that LPS causes selective activation of the proteasome in macrophage rafts and proteasome inactivation outside of rafts. Given previous reports of an essential role for proteasomal degradation of IkappaB kinase-phosphorylated p105 in LPS activation of ERK mitogen-activated protein kinase, we tested for a role of rafts in compartmentalization of these events. Immunoblotting of DRMs revealed proteasome-dependent activation of MEK and ERK specifically occurring in lipid rafts as well as proteasomal activity upon raft-localized p105 that was enhanced by LPS. Cholesterol extraction from the intact macrophage with methyl-beta-cyclodextrin was sufficient to activate ERK, recapitulating the LPS-IkappaB kinase-p105-MEK-ERK cascade, whereas both it and the alternate raft-disrupting agent nystatin blocked subsequent LPS activation of the ERK cascade. Taken together, our findings indicate a critical, selective role for raft compartmentalization and regulation of proteasome activity in activation of the MEK-ERK pathway.

18th World Congress on Ultrasound in Obstetrics and Gynecology, 24–28 August 2008, Chicago, USA: presentations and awards

When asked to introduce Larry Platt as the 2008 Gold Medal recipient, I was more than delighted to do so. One might consider this to be a daunting task. However, since Larry’s career is so robust, it was actually easy to chronicle his contributions through the years. To me, the Ian Donald Gold Medal Award is the greatest honor that one can receive in our field of obstetric and gynecological ultrasonography. Since it carries so much respect, when I heard that Larry Platt was this year’s recipient I thought to myself, ‘it’s about time’. Why? Firstly, Larry has been a prolific contributor to the literature. Secondly, he has been a tenacious supporter of ultrasound education. And thirdly, aside from Stuart Campbell, I can think of no one who has been a greater advocate for ISUOG. He has served as President of the Society, Associate Editor of Ultrasound in Obstetrics and Gynecology, and has been on the Board for many years; he has simply put ISUOG first, ahead of his many other responsibilities. When I recently thumbed through my most recent book on ultrasound, I found that I had cited Larry’s work in five different chapters. First and foremost, one cannot mention his name without connecting it to the wonderful contribution that he and Frank Manning made in designing the biophysical profile. It is hard to believe that this was published 28 years ago, and is still being used in its original form by virtually everyone managing

On solution of total least squares problems with multiple right‐hand sides

AbstractConsider a linear approximation problem AX≈B with multiple right–hand sides. When errors in the data are confirmed both to B and A, the total least squares (TLS) concept is used to solve this problem. Contrary to the standard least squares approximation problem, a solution of the TLS problem may not exist. For a single (vector) right–hand side, the classical theory has been developed by G.H. Golub, C.F. Van Loan [2], and S. Van Huffel, J. Vandewalle [4], and then complemented recently by the core problem approach of C.C. Paige, Z. Strakoš [5,6,7]. Analysis of the problem with multiple right–hand sides is still under development. In this short contribution we present conditions for the existence of a TLS solution. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

GLOBAL CONVERGENCE OF RTLSQEP: A SOLVER OF REGULARIZED TOTAL LEAST SQUARES PROBLEMS VIA QUADRATIC EIGENPROBLEMS

The total least squares (TLS) method is a successful approach for linear problems if both the matrix and the right hand side are contaminated by some noise. In a recent paper Sima, Van Huffel and Golub suggested an iterative method for solving regularized TLS problems, where in each iteration step a quadratic eigenproblem has to be solved. In this paper we prove its global convergence, and we present an efficient implementation using an iterative projection method with thick updates.

Regularized total least squares based on the nonlinear Arnoldi method

AbstractA computational approach for solving regularized total least squares problems via a sequence of quadratic eigenvalue problems has recently been introduced by Sima, Van Huffel, and Golub. Combining this approach with the nonlinear Arnoldi method and reusing information from all previous quadratic eigenvalue problems, together with an early update of search spaces we arrive at a very efficient method for large regularized total least squares problems. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)