26 research outputs found
Synthese von Bildern mittels parametrisierter Modelle für die automatische optische Inspektion (AOI)
No full textS.251-261Bei Entwurf und Optimierung von Systemen zur automatischen optischen Inspektion ist eine systematische Evaluierung von großer Bedeutung, um hohe Qualität zu erreichen und zu garantieren, zugleich aber *Corresponding author: Max-Gerd Retzlaff, Karlsruhe Institute of Technology (KIT), Institute for Visualization and Data Analysis, Computer Graphics Group, Karlsruhe; and Fraunhofer Institute of Optronics, System Technologies and Image Exploitation (IOSB), Karlsruhe, e-mail: [email protected] Josua Stabenow, Carsten Dachsbacher: Karlsruhe Institute of Technology (KIT), Institute for Visualization and Data Analysis, Computer Graphics Group, Karlsruhe Jürgen Beyerer: Karlsruhe Institute of Technology (KIT), Institute for Anthropomatics and Robotics, Vision and Fusion Laboratory (IES), Karlsruhe; and Fraunhofer Institute of Optronics, System Technologies and Image Exploitation (IOSB), Karlsruhe kostspielig. Methoden der Computergrafik können eingesetzt werden, um schnell große virtuelle Kontrollproben von Testobjekten zu erzeugen und die Bildgewinnung zu simulieren. Wir verwenden Techniken der prozeduralen Modellierung, um virtuelle Objekte in großer Vielfalt und mit variantenreichem Aussehen zu erzeugen, die reale Objekte und Messproben nachahmen. Physikalische Simulation von Starrkörpern wird verwendet, um die Platzierung der virtuellen Objekte zu simulieren, und mit physikalisch basierten Rendering-Methoden erzeugen wir synthetische Bilder. Diese Bilder werden als Eingabe für ein AOI-System anstatt physikalisch gewonnener Bilder eingesetzt. Dieses Vorgehen erlaubt eine Entwicklung, Verbesserung und Evaluierung der Bildverarbeitungs- und Klassifikationsschritte eines AOI-Systems unabhängig von einer physischen Realisierung. Wir demonstrieren den vorgestellten Ansatz für Glasscherben, da die Glassortierung eine anspruchsvolle praktische Anwendung der AOI darstellt.When designing or improving systems for automated optical inspection (AOI), systematic evaluation is an important but costly necessity to achieve and ensure high quality. Computer graphics methods can be used to quickly create large virtual sets of samples of test objects and to simulate image acquisition setups. We use procedural modeling techniques to generate virtual objects with varying appearance and properties, mimicking real objects and sample sets. Physical simulation of rigid bodies is deployed to simulate the placement of virtual objects, and using physically-based rendering techniques we create synthetic images. These are used as input to an AOI system instead of physically acquired images. This enables the development, optimization, and evaluation of the image processing and classification steps of an AOI system independently of a physical realization. We demonstrate this approach for shards of glass, as sorting glass is one challenging practical application for AOI.82Nr.
<i>Drei Haselnüsse für Aschenbrödel</i>
No full textSummary
‚Three Wishes for Cinderella‘ (Tři oříšky pro Popelku / Drei Haselnüsse für Aschenbrödel) is one of the most successful fairy tale films in Czech and German TV. Produced in 1973, it is shown up to now regularly around Christmas in both countries. Every year around the same time, at Moritzburg Castle near Dresden, which has been chosen as place of the ball in the movie, one can see a special Cinderella exhibition. In his paper the author investigates the question of the success of this film. He presents the conditions of the Czech-German joint production during the time of the so called normalisation after the Prague Spring. He compares the story and figures with its literary models (Božena Němcová, Brothers Grimm), and discusses some theories about the modernity of characters, especially of Cinderella as a modern emancipated woman. The core of the paper is the analysis of the narrative structure itself, which may be considered as the secret to the success of the movie.</jats:p
Importance of cerebrospinal fluid analysis in the era of McDonald 2010 criteria: a German-Austrian retrospective multicenter study in patients with a clinically isolated syndrome
No full textThe majority of patients presenting with a first clinical symptom suggestive of multiple sclerosis (MS) do not fulfill the MRI criteria for dissemination in space and time according to the 2010 revision of the McDonald diagnostic criteria for MS and are thus classified as clinically isolated syndrome (CIS). To re-evaluate the utility of cerebrospinal fluid (CSF) analysis in the context of the revised McDonald criteria from 2010, we conducted a retrospective multicenter study aimed at determining the prevalence and predictive value of oligoclonal IgG bands (OCBs) in patients with CIS. Patients were recruited from ten specialized MS centers in Germany and Austria. We collected data from 406 patients; at disease onset, 44/406 (11 %) fulfilled the McDonald 2010 criteria for MS. Intrathecal IgG OCBs were detected in 310/362 (86 %) of CIS patients. Those patients were twice as likely to convert to MS according to McDonald 2010 criteria as OCB-negative individuals (hazard ratio = 2.1, p = 0.0014) and in a shorter time period of 25 months (95 % CI 21-34) compared to 47 months in OCB-negative individuals (95 % CI 36-85). In patients without brain lesions at first attack and presence of intrathecal OCBs (30/44), conversion rate to MS was 60 % (18/30), whereas it was only 21 % (3/14) in those without OCBs. Our data confirm that in patients with CIS the risk of conversion to MS substantially increases if OCBs are present at onset. CSF analysis definitely helps to evaluate the prognosis in patients who do not have MS according to the revised McDonald criteria
Studying language evolution in the age of big data
No full textThe increasing availability of large digital corpora of cross-linguistic data is revolutionizing many branches of linguistics. Overall, it has triggered a shift of attention from detailed questions about individual features to more global patterns amenable to rigorous, but statistical, analyses. This engenders an approach based on successive approximations where models with simplified assumptions result in frameworks that can then be systematically refined, always keeping explicit the methodological commitments and the assumed prior knowledge. Therefore, they can resolve disputes between competing frameworks quantitatively by separating the support provided by the data from the underlying assumptions. These methods, though, often appear as a 'black box' to traditional practitioners. In fact, the switch to a statistical view complicates comparison of the results from these newer methods with traditional understanding, sometimes leading to misinterpretation and overly broad claims. We describe here this evolving methodological shift, attributed to the advent of big, but often incomplete and poorly curated data, emphasizing the underlying similarity of the newer quantitative to the traditional comparative methods and discussing when and to what extent the former have advantages over the latter. In this review, we cover briefly both randomization tests for detecting patterns in a largely model-independent fashion and phylolinguistic methods for a more model-based analysis of these patterns. We foresee a fruitful division of labor between the ability to computationally process large volumes of data and the trained linguistic insight identifying worthy prior commitments and interesting hypotheses in need of comparison. © The Author(s) 2018. Published by Oxford University Press. All rights reserved
Longitudinal optic neuritis-unrelated visual evoked potential changes in NMO spectrum disorders
No full textOBJECTIVE: To investigate if patients with neuromyelitis optica spectrum disorder (NMOSD) develop subclinical visual pathway impairment independent of acute attacks: METHODS: A total of 548 longitudinally assessed full-field visual evoked potentials (VEP) of 167 patients with NMOSD from 16 centers were retrospectively evaluated for changes of P100 latencies and P100-N140 amplitudes. Rates of change in latencies (RCL) and amplitudes (RCA) over time were analyzed for each individual eye using linear regression and compared using generalized estimating equation models. RESULTS: The rates of change in the absence of optic neuritis (ON) for minimal VEP intervals of ≥3 months between baseline and last follow-up were +1.951 ms/y (n = 101 eyes; SD = 6.274; p = 0.012) for the P100 latencies and -2.149 µV/y (n = 64 eyes; SD = 5.013; p = 0.005) for the P100-N140 amplitudes. For minimal VEP intervals of ≥12 months, the RCL was +1.768 ms/y (n = 59 eyes; SD = 4.558; p = 0.024) and the RCA was −0.527 µV/y (n = 44 eyes; SD = 2.123; p = 0.111). The history of a previous ON >6 months before baseline VEP had no influence on RCL and RCA. ONs during the observational period led to mean RCL and RCA of +11.689 ms/y (n = 16 eyes; SD = 17.593; p = 0.003) and -1.238 µV/y (n = 11 eyes; SD = 3.708; p = 0.308), respectively. CONCLUSION: This first longitudinal VEP study of patients with NMOSD provides evidence of progressive VEP latency delay occurring independently of acute ON. Prospective longitudinal studies are needed to corroborate these findings and help to interpret the clinical relevance
The accuracy of the double-K adjustment for third-generation intraocular lens calculation formulas in previous keratorefractive surgery eyes
No full textPurpose: To evaluate the effect of the double-K (DK) modification on third-generation formulas. Methods: Thirty-eight previously myopic and 24 previously hyperopic eyes that underwent phacoemulsification with intraocular lens (IOL) insertion after Laser in situ keratomileusis (LASIK) were evaluated. Pre-LASIK refraction and keratometry, post-LASIK topography, axial length (AL), IOL type and power, and 1-month postphacoemulsification refraction were recorded spherical equivalent after phacoemulsification (SEpostphaco). Measured corneal power was adjusted using published and validated methods for postmyopic and posthyperopic LASIK. For each eye, and using SEpostphaco, different DK-IOL formulas were used to calculate the corresponding IOL power, the outcome measure, which was compared with the implanted IOL. Results: DK-Holladay 1 yielded the highest Pearson correlation coefficient (PCC), 0.955 for myopes and 0.943 for high myopes (AL26 mm). Mean error (ME) and mean absolute error (MAE) for myopes for DK Sanders-Retzlaff-Kraff theoretical formula [DK-SRK-T] were 0.44±0.84 D and 0.75±0.61 D for DK-SRK-T compared with-0.04±0.67 D and 0.52±0.40 D for DK-Holladay 1 (P0.001 and P=0.016, respectively), and 0.03±0.88 and 0.64±0.58 for DK-Hoffer Q. For high myopes, ME and MAE were 0.75±0.81 D and 0.84±0.69 D for DK-SRK-T, and-0.05±0.74 D (P0.0001) and 0.57±0.45 D (P=0.019) for DK-Holladay 1. About 29percent of DK-SRK-T eyes with large AL had MAE1.5 D, compared with 0percent for DK-Holladay 1 and 14percent for DK-Hoffer-Q. Eyes with previous hyperopic LASIK faired similarly for all formulas, with similar PCCs, and only 8percent in each category with MAE1.5 D. Conclusions: DK-SRK-T overestimates IOL power in eyes with large AL, especially with concomitant steep pre-lasik keratometry. Among third-generation formulas, DK-Holladay 1 seems more accurate to use in postmyopic LASIK eyes. © 2013 Contact Lens Association of Ophthalmologists.Aramberri J, 2003, J CATARACT REFR SURG, V29, P2063, DOI 10.1016-S0886-3350(03)00232-3; Awwad ST, 2009, OPHTHALMOLOGY, V116, P393, DOI 10.1016-j.ophtha.2008.09.045; Awwad ST, 2008, J CATARACT REFR SURG, V34, P1070, DOI 10.1016-j.jcrs.2008.03.020; Awwad ST, 2007, J CATARACT REFR SURG, V33, P1045, DOI 10.1016-j.jcrs.2007.03.018; Borasio E, 2006, J CATARACT REFR SURG, V32, P2004, DOI 10.1016-j.jcrs.2006.08.037; Feiz V, 2001, CORNEA, V20, P792, DOI 10.1097-00003226-200111000-00003; HAIGIS W, 1993, J CATARACT REFR SURG, V19, P442; HOFFER KJ, 1993, J CATARACT REFR SURG, V19, P700; Hoffer KJ, 2002, ARCH OPHTHALMOL-CHIC, V120, P500; Hoffer KJ, 2000, J CATARACT REFR SURG, V26, P1233, DOI 10.1016-S0886-3350(00)00376-X; HOLLADAY JT, 1988, J CATARACT REFR SURG, V14, P17; Ianchulev T, 2005, J CATARACT REFR SURG, V31, P1530, DOI 10.1016-j.jcrs.2005.01.035; Kalski RS, 1997, J REFRACT SURG, V13, P362; Langenbucher Achim, 2004, Curr Opin Ophthalmol, V15, P1, DOI 10.1097-00055735-200402000-00002; Livingston EH, 2004, J SURG RES, V119, P117, DOI 10.1016-j.jss.2004.02.008; Mackool RJ, 2006, J CATARACT REFR SURG, V32, P435, DOI 10.1016-j.jcrs.2005.11.045; Masket S, 2006, J CATARACT REFR SURG, V32, P430, DOI 10.1016-j.jcrs.2005.12.106; Narvaez J, 2006, J CATARACT REFR SURG, V32, P2050, DOI 10.1016-j.jcrs.2006.09.009; Odenthal MTP, 2003, ARCH OPHTHALMOL-CHIC, V121, P1071, DOI 10.1001-archopht.121.7.1071; Randleman JB, 2002, CORNEA, V21, P751, DOI 10.1097-00003226-200211000-00003; RETZLAFF JA, 1990, J CATARACT REFR SURG, V16, P333; Rosa N, 2002, J REFRACT SURG, V18, P720; Rosa N, 2005, J CATARACT REFR SURG, V31, P254, DOI 10.1016-j.jcrs.2004.12.014; SANDERS DR, 1990, J CATARACT REFR SURG, V16, P341; Seitz B, 2000, Curr Opin Ophthalmol, V11, P35, DOI 10.1097-00055735-200002000-00006; Seitz B, 2000, J REFRACT SURG, V16, P349; Seitz B, 1999, OPHTHALMOLOGY, V106, P693, DOI 10.1016-S0161-6420(99)90153-7; Siganos DS, 1996, J REFRACT SURG, V12, pS278; Tsang CSL, 2003, J CATARACT REFR SURG, V29, P1358, DOI 10.1016-S0886-3350(02)01976-4; Wang L, 2002, J CATARACT REFR SURG, V28, P954, DOI 10.1016-S0886-3350(02)01318-4; Wang L, 2004, OPHTHALMOLOGY, V111, P1825, DOI 10.1016-j.ophtha.2004.04.0220
Different pain phenotypes are associated with anti-Caspr2 autoantibodies
No full textGreguletz P, Plotz M, Baade-Buttner C, et al. Different pain phenotypes are associated with anti-Caspr2 autoantibodies. Journal of neurology. 2024.Autoantibodies against contactin-associated protein 2 (Caspr2) not only induce limbic autoimmune encephalitis but are also associated with pain conditions. Here, we analyzed clinical data on pain in a large cohort of patients included into the German Network for Research in Autoimmune Encephalitis. Out of 102 patients in our cohort, pain was a frequent symptom (36% of all patients), often severe (63.6% of the patients with pain) and/or even the major symptom (55.6% of the patients with pain). Pain phenotypes differed between patients. Cluster analysis revealed two major phenotypes including mostly distal-symmetric burning pain and widespread pain with myalgia and cramps. Almost all patients had IgG4 autoantibodies and some additional IgG1, 2, and/or 3 autoantibodies, but IgG subclasses, titers, and presence or absence of intrathecal synthesis were not associated with the occurrence of pain. However, certain pre-existing risk factors for chronic pain like diabetes mellitus, peripheral neuropathy, or preexisting chronic back pain tended to occur more frequently in patients with anti-Caspr2 autoantibodies and pain. Our data show that pain is a relevant symptom in patients with anti-Caspr2 autoantibodies and support the idea of decreased algesic thresholds leading to pain. Testing for anti-Caspr2 autoantibodies needs to be considered in patients with various pain phenotypes. © 2024. The Author(s)
Update on the diagnosis and treatment of neuromyelitis optica spectrum disorders (NMOSD) – revised recommendations of the Neuromyelitis Optica Study Group (NEMOS). Part II: Attack therapy and long-term management
No full textInternational audienceThis manuscript presents practical recommendations for managing acute attacks and implementing preventive immunotherapies for neuromyelitis optica spectrum disorders (NMOSD), a rare autoimmune disease that causes severe inflammation in the central nervous system (CNS), primarily affecting the optic nerves, spinal cord, and brainstem. The pillars of NMOSD therapy are attack treatment and attack prevention to minimize the accrual of neurological disability. Aquaporin-4 immunoglobulin G antibodies (AQP4-IgG) are a diagnostic marker of the disease and play a significant role in its pathogenicity. Recent advances in understanding NMOSD have led to the development of new therapies and the completion of randomized controlled trials. Four preventive immunotherapies have now been approved for AQP4-IgG-positive NMOSD in many regions of the world: eculizumab, ravulizumab - most recently-, inebilizumab, and satralizumab. These new drugs may potentially substitute rituximab and classical immunosuppressive therapies, which were as yet the mainstay of treatment for both, AQP4-IgG-positive and -negative NMOSD. Here, the Neuromyelitis Optica Study Group (NEMOS) provides an overview of the current state of knowledge on NMOSD treatments and offers statements and practical recommendations on the therapy management and use of all available immunotherapies for this disease. Unmet needs and AQP4-IgG-negative NMOSD are also discussed. The recommendations were developed using a Delphi-based consensus method among the core author group and at expert discussions at NEMOS meetings
Experiencing and Learning from Entrepreneurial Failure
No full textEntrepreneurship literature has long focused on stories of entrepreneurial success. However, in recent years consensus has begun to build around the importance of also studying failure in order to develop a more holistic understanding of entrepreneurship. It has been argued that failure can have an impact on entrepreneurial decision-making in subsequent ventures and can be a difficult experience for an entrepreneur to go through. In spite of such speculations and acknowledgements, failure remains a relatively underresearched area, except perhaps from the primary perspective of the reasons behind failure. While this is an important area of investigation − as understanding reasons behind failure can improve the probability of success in subsequent entrepreneurial endeavours – it is equally important to understand the experience of failure. The primary aim of this thesis is to understand failure from the perspective of entrepreneurs who have experienced it. Its second aim is to build a theoretical framework of failure based on those experiences.
The overarching research question for this study is: “How do entrepreneurs experience venture failure and learn from this experience?” The three supporting subquestions are: “What do entrepreneurs experience when their venture fails?”, “How do entrepreneurs stay resilient when the venture fails?”, and “What do the entrepreneurs learn from experiencing venture failure?” Using the philosophical position of interpretive, phenomenological symbolic interactionism and narrative as a strategy of inquiry, stories of failure as told by 21 entrepreneurs during in-depth interviews are analysed. Using the metaphor of fabric tear and repair, theoretical constructs developed from the findings are integrated into a framework and discussed in the light of relevant literature. The framework highlights that failure leads to considerable challenges for the entrepreneurs and triggers grief. After grief, however, comes resilience. In this journey, resilience came from acceptance and hope, states that shifted the entrepreneurs’ perspective on venture failure from one which saw it as a negative, end-all event to one that framed it as a challenging, survivable event. This resilience fuelled their efforts to adapt to their changed reality. Grief faded as entrepreneurs dealt with the challenges. From this experience, the entrepreneurs learnt business lessons and transformed in such a way as to become more spiritually inclined.
The study extends the understanding of the phenomenon of failure in entrepreneurship by presenting an empirical evidence-based framework that incorporates failure-related challenges, entrepreneurs’ adaptation to these challenges, and the lessons learnt from this experience. Second, this study illustrates the importance of hope and acceptance in building entrepreneurial resilience, and how entrepreneurs’ social environment and sometimes spiritual beliefs play an important role in nurturing hope and an acceptance of adapting to the challenges. Policy makers, educators, and entrepreneurs can benefit from the findings of this study as it highlights factors leading to failure, the repercussions of it. The study also shows how failure, although an undesirable experience, can be utilised as a springboard to bounce into a satisfying career by tapping into one’s spiritual beliefs, support networks, and resources within the social environment.
Übertragbarkeit der gesundheitsökonomischen Evaluationen : Methoden für die multinationalen Studien
No full textFilonenko A. Generalizability of health economic evaluations : methods for multinational patient-level studies. Bielefeld (Germany): Bielefeld University; 2010.Background: Cost-effectiveness outcomes collected in multinational health economic studies may vary across countries and geographic areas due to numerous clinical and socioeconomic factors. The between-country variability poses the question of generalizability of the cost-effectiveness estimates, i.e. applicability of the trial-wide results for the decision-making in particular jurisdiction.
Objectives: The purpose of this research is to illustrate how selected methods can improve generalizability of the results of patient-level health economic studies by a) exploring between-country variability in incremental costs, effectiveness and resource use, b) calculation of trial-wide and country-level incremental cost, effectiveness and resource use while accounting for patient- and country-level covariates, and c) assessing the potential of covariates to predict cost and effectiveness estimates for the settings outside the study.
Methods: Review of published health-economic evidence and international HTA guidelines was conducted to evaluate applied or recommended methods and analytical strategies to improve generalizability of the health economic outcomes. In the case study, qualitative and quantitative homogeneity test by Simon and Gail is used to explore between-country heterogeneity of the treatment effects measured by incremental costs, effectiveness, resource use (length of hospitalization) and incremental net monetary benefit. Hierarchical modelling is applied to calculate trial-wide and country-level estimates, while accounting for clustering and incorporating country- and patient-level covariates.
Results: Simon and Gail test indicated qualitative homogeneity for incremental effectiveness, costs, length of hospitalization and net monetary benefit between treatment and control arms. Trial-wide and country-level mean incremental costs and effectiveness were estimated using hierarchical models with and without covariates. Results of hierarchical modelling suggested, that new treatment was more efficacious, saved costs and resource use in majority of the countries.
Conclusions: Homogeneity test and hierarchical models are complementary methods to explore heterogeneity and to estimate trial-wide and country-level parameters for cost-effectiveness analysis. Hierarchical models allow for country-level estimates and adjustment for covariates. In the case study the patient-level covariates showed effect on incremental cost and effectiveness; country-level covariates had very small impact on estimates. The use of country-level covariates as predictors for incremental cost and resource use to improve generalizability of health economic studies beyond the study setting merits further investigation
