936 research outputs found

    Can I Trust My One-Class Classification?

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    Contrary to binary and multi-class classifiers, the purpose of a one-class classifier for remote sensing applications is to map only one specific land use/land cover class of interest. Training these classifiers exclusively requires reference data for the class of interest, while training data for other classes is not required. Thus, the acquisition of reference data can be significantly reduced. However, one-class classification is fraught with uncertainty and full automatization is difficult, due to the limited reference information that is available for classifier training. Thus, a user-oriented one-class classification strategy is proposed, which is based among others on the visualization and interpretation of the one-class classifier outcomes during the data processing. Careful interpretation of the diagnostic plots fosters the understanding of the classification outcome, e.g., the class separability and suitability of a particular threshold. In the absence of complete and representative validation data, which is the fact in the context of a real one-class classification application, such information is valuable for evaluation and improving the classification. The potential of the proposed strategy is demonstrated by classifying different crop types with hyperspectral data from Hyperion

    Untersuchungen zum Schadensmechanismus Torsionsschwingbruch durch Kontaktermüdung an Schraubendruckfedern

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    Im Rahmen der vorliegenden Arbeit werden die Wirkzusammenhänge des Schadensmechanismus „Torsionsschwingbruch durch Kontaktermüdung“ untersucht und Möglichkeiten zur Quantifizierung des Schadensmechanismus aufgezeigt. Hierfür werden Federvarianten mit unterschiedlichen Anlageverhalten gefertigt, charakterisiert und geprüft. Mit den bisher etablierten Methoden kann das Anlageverhalten nicht lokal und zugleich bei einer definierten Federkraft bewertet werden. Vor diesem Hintergrund wird die Lichtspaltmethode entwickelt. Die Lichtspaltmethode eignet sich im Gegensatz zu numerischen Verfahren auch zur fertigungsnahen Beurteilung des Anlageverhaltens. Zusätzlich ermöglicht die Lichtspaltmethode einen höherwertigen FE-Abgleich im Endwindungsbereich, als ein Abgleich über die Federrate oder mittels druckempfindlichen Papiers. Auf Grundlage der Schwingfestigkeitsversuche an Schraubendruckfedern, den Erkenntnissen aus dem lokalen und kraftabhängigen Anlageverhalten im Endwindungsbereich sowie numerischen Berechnungen wird abschließend eine Vorgehensweise zur Auslegung der Endwindungsgeometrie bei erhöhter Schwingspielzahl aufgezeigt.The target of this paper is to examine the cause-effect relationships of the damage mechanism „torsion fatigue failure through contact fatigue“ and to point out options for quantification of the damage mechanism. For this purpose, spring variants with different end coil contact behaviours are produced, characterised and tested. The methods established to date cannot assess the end coil contact behaviour locally and at the same time at a defined spring force, which is required for the production of test springs with specifically varying end coil contact behaviour. The light-gap method is developed based on this requirement. The light-gap method, in contrast to the numerical procedures, is also suitable for production-related assessment of the end coil contact behaviour. Additionally, the light-gap method permits higher-quality FE reconciliation in the end coil area than reconciliation via the spring rate or by pressure-sensitive paper. Based on the fatigue tests results, the damage mechanism is broken down into high cycle contact fatigue with the fracture starting in the area close to the surface and very high cycle contact fatigue with the fracture starting below the surface. Supporting examinations on springs and wires indicate that causes contributing to end coil failures in high cycle contact fatigue are due to production- or wear-related primary damage. End coil failures in the area of very high cycles with a fracture starting below the surface indicate primary damage from contact fatigue crack formation. A procedure for design of the end coil geometry at very high cycles is developed based on spring fatigue tests and numeric calculations. The general design of the end coil geometry takes place via analysis of the contact angle depending on the torsion stress. The local evaluation is performed based on the finite element method and suitable damage parameters. The numeric recalculation of the fatigue tests shows that the local contact pressure range as well as the damage parameter according to Dang Van are suitable parameters to describe very high cycle contact fatigue. This work permits local evaluation of end coil breaks from contact fatigue in the very high cycle area.Ziel der vorliegenden Arbeit ist es, die Wirkzusammenhänge des Schadensmechanismus „Torsionsschwingbruch durch Kontaktermüdung“ zu untersuchen und Möglichkeiten zur Quantifizierung des Schadensmechanismus aufzuzeigen. Zu diesem Zweck werden Federvarianten mit unterschiedlichen Anlageverhalten gefertigt, charakterisiert und geprüft. Mit den bisher etablierten Methoden kann das Anlageverhalten nicht lokal und zugleich bei einer definierten Federkraft bewertet werden, was für die Fertigung von Versuchsfedern mit gezielt variierenden Anlageverhalten erforderlich ist. Vor diesem Hintergrund wird die Lichtspaltmethode entwickelt. Die Lichtspaltmethode eignet sich im Gegensatz zu numerischen Verfahren auch zur fertigungsnahen Beurteilung des Anlageverhaltens. Zusätzlich ermöglicht die Lichtspaltmethode einen höherwertigen FE-Abgleich im Endwindungsbereich, als ein Abgleich über die Federrate oder mittels druckempfindlichen Papiers. Aufgrund der Schwingfestigkeitsergebnisse wird eine Untergliederung des Schadensmechanismus hinsichtlich HCF-Kontaktermüdung mit Bruchausgang im Oberflächennahen Bereich und VHCF-Kontaktermüdung mit Bruchausgang unterhalb der Oberfläche vorgenommen. Begleitender Untersuchungen an Federn und Drähten zeigen, dass begünstigende Ursachen für Endwindungsbrüche mit der Ausprägung HCF-Kontaktermüdung sich auf eine fertigungs- bzw. verschleißbedingte Primärschädigung zurückführen lassen. Endwindungsbrüche im Bereich erhöhter Schwingspielzahlen mit einem Bruchausgang unterhalb der Oberfläche weisen auf eine Primärschädigung durch Kontaktermüdungsrissbildung hin. Auf Grundlage der Schwingfestigkeitsversuche an Schraubendruckfedern und numerischen Berechnungen wird eine Vorgehensweise zur Auslegung der Endwindungsgeometrie bei erhöhter Schwingspielzahl erarbeitet. Die Grobauslegung der Endwindungsgeometrie erfolgt über die Analyse des Kontaktwinkels in Abhängigkeit der Torsionsbeanspruchung. Die örtliche Bewertung erfolgt auf Basis der Finiten Elemente Methode und geeigneter Schadensparameter. Die numerische Nachrechnung der Schwingversuche zeigt, dass die lokale Kontaktdruckschwingweite als auch der Schadensparameter nach Dang Van geeignete Kenngrößen zur Beschreibung der VHCF-Kontaktermüdung darstellen. Durch diese Arbeit lassen sich Endwindungsbrüche durch Kontaktermüdung im VHCF-Bereich lokal bewerten

    Mapping paddy rice in Asia: a multi-sensor, time-series approach.

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    Rice is the most important food crop in Asia and the mapping and monitoring of paddy rice fields is an important task in the context of food security, food trade policy and greenhouse gas emissions modelling. Two countries where rice is of special significance are China, the largest producer and importer of rice, and Vietnam, where rice exports contribute a fifth to the GDP. Both countries are facing increasing pressure in terms of food security due to population and economic growth while agricultural areas are confronted with urban encroachment and the limits of yield increase. Despite the importance of knowledge about rice production the countries official land cover products and rice production statistics are of varying quality and sometimes even contradict each other. Available remote sensing studies focused either on time-series analysis from optical sensors or from Synthetic Aperture Radar (SAR) sensors – the studies using optical sensors faced problems due to either the spatial or temporal resolution and the persistent cloud cover while SAR studies found the limited data availability and large image size to be the biggest drawbacks. We try to address these issues by proposing a paddy rice mapping approach that combines medium spatial resolution, temporally dense time-series from the optical MODIS sensors and high spatial resolution time-series from the recently launched Sentinel-1 SAR sensor. We used the 250m resolution MOD13Q1 and MYD13Q1 products as a basis for our medium resolution rice map. Prevalent cloud cover introduces noise into these timeseries which we reduced by applying a Savitzky-Golay filter. We then derived a number of time-series temporal and phenological metrics for multiple years and classified rice areas with One Class Support Vector Machines. In a next step we used this medium resolution rice map to mask Sentinel-1 Interferometric Wide Swath images and create SAR time-series from which we again derived temporal and phenological metrics and classified rice areas with machine learning algorithms to arrive at a 10m resolution rice map. This method allows concurrent, accurate and high resolution mapping of paddy rice areas from freely available data with limited requirements towards processing infrastructure and can be used as a basis for greenhouse gas and crop modelling as well as providing viable information for decision makers regarding food security, food trade, bioeconomy and mitigation after crop failure. Results of our paddy rice classification will be presented for selected study sites in China and Vietnam

    CDKN1C/p57kip2 Is a Candidate Tumor Suppressor Gene in Human Breast Cancer

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    BACKGROUND. CDKN1C (also known as p57KIP2) is a cyclin-dependent kinase inhibitor previously implicated in several types of human cancer. Its family members (CDKN1A/p21CIP1 and B/p27KIP1) have been implicated in breast cancer, but information about CDKN1C's role is limited. We hypothesized that decreased CDKN1C may be involved in human breast carcinogenesis in vivo. METHODS. We determined rates of allele imbalance or loss of heterozygosity (AI/LOH) in CDKN1C, using an intronic polymorphism, and in the surrounding 11p15.5 region in 82 breast cancers. We examined the CDKN1C mRNA level in 10 cancers using quantitative real-time PCR (qPCR), and the CDKN1C protein level in 20 cancers using immunohistochemistry (IHC). All samples were obtained using laser microdissection. Data were analyzed using standard statistical tests. RESULTS. AI/LOH at 11p15.5 occurred in 28/73 (38%) informative cancers, but CDKN1C itself underwent AI/LOH in only 3/16 (19%) cancers (p = ns). In contrast, CDKN1C mRNA levels were reduced in 9/10 (90%) cancers (p < 0.0001), ranging from 2–60% of paired normal epithelium. Similarly, CDKN1C protein staining was seen in 19/20 (95%) cases' normal epithelium but in only 7/14 (50%) cases' CIS (p < 0.004) and 5/18 (28%) cases' IC (p < 0.00003). The reduction appears primarily due to loss of CDKN1C expression from myoepithelial layer cells, which stained intensely in 17/20 (85%) normal lobules, but in 0/14 (0%) CIS (p < 0.00001). In contrast, luminal cells displayed less intense, focal staining fairly consistently across histologies. Decreased CDKN1C was not clearly associated with tumor grade, histology, ER, PR or HER2 status. CONCLUSION. CDKN1C is expressed in normal epithelium of most breast cancer cases, mainly in the myothepithelial layer. This expression decreases, at both the mRNA and protein level, in the large majority of breast cancers, and does not appear to be mediated by AI/LOH at the gene. Thus, CDKN1C may be a breast cancer tumor suppressor.Department of Defense Breast Cancer Research Program (DAMD 17-99-1-9573); National Institutes of Health PHS (CA081078); LaPann Fun

    Assessing Forest Cover Dynamics and Forest Perception in the Atlantic Forest of Paraguay, Combining Remote Sensing and Household Level Data

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    The Upper Parana Atlantic Forest (BAAPA) in Paraguay is one of the most threatened tropical forests in the world. The rapid growth of deforestation has resulted in the loss of 91% of its original cover. Numerous efforts have been made to halt deforestation activities, however farmers’ perception towards the forest and its benefits has not been considered either in studies conducted so far or by policy makers. This research provides the first multi-temporal analysis of the dynamics of the forest within the BAAPA region on the one hand, and assesses the way farmers perceive the forest and how this influences forest conservation at the farm level on the other. Remote sensing data acquired from Landsat images from 1999 to 2016 were used to measure the extent of the forest cover and deforestation rates over 17 years. Farmers’ influence on the dynamics of the forest was evaluated by combining earth observation data and household survey results conducted in the BAAPA region in 2016. Outcomes obtained in this study demonstrate a total loss in forest cover of 7500 km 2 . Deforestation rates in protected areas were determined by management regimes. The combination of household level and remote sensing data demonstrated that forest dynamics at the farm level is influenced by farm type, the level of dependency/use of forest benefits and the level of education of forest owners. An understanding of the social value awarded to the forest is a relevant contribution towards preserving natural resources

    Assessment of the Severity of Paravalvular Regurgitation and its Role on Survival After Transcatheter Aortic Valve Replacement

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    Background: To evaluate the impact of various measurements of paravalvular regurgitation (PVR) on survival after transcatheter aortic valve replacement (TAVR). PVR can be difficult to grade and both its incidence and impact on survival may be decreasing as TAVR evolves. Methods: This retrospective study included 911 patients undergoing TAVR in two institutions. PVR was graded according to the 3-grade scheme proposed by the guidelines (PVR grade), and subsequently grade 2 and 3, and grade 0 and 1 were lumped together. PVR was also graded as a composite score (PVR score), based on 6 commonly used metrics. PVR grade, PVR score and its six individual components were tested against the risk of both 1-year and longer term mortality after TAVR. Results: Patients with moderate/severe PVR had a higher Society of Thoracic Sugeons (STS) score, higher levels of serum creatinine and larger left atria compared to patients with none/mild PVR. Moderate/severe PVR was more frequent with self-expandable and larger valves. After adjusting for American College of Cardiology (ACC) TAVR risk score, neither PVR grade, PVR score nor its six components were associated with an increased risk of mortality at 1-year (severe PVR adjusted HR: 0.75, 95% Confidence Interval [CI]: 0.19, 3.01, p = 0.50). However, intervention for clinically severe PVR increased the risk of mortality by more than 7-fold (adjusted hazard ratio [HR]: 7.6, 95% CI: 2.4, 23.5, p < 0.0001). Conclusions: In the contemporary era, moderate-severe PVR is uncommon. However, re-intervention for PVR portends a poor prognosis. This highlights the crucial importance of clinical judgment over imaging alone

    Nutrient-specific solubility patterns of leaf litter across 41 lowland tropical woody species

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    Abstract. Leaching is a mechanism for the release of nutrients from litter or senesced leaves that can drive interactions among plants, microbes, and soil. Although leaching is well established in conceptual models of litter decomposition, potential nutrient solubility of mineral elements from recently senesced litter has seldom been quantified. Using a standardized extraction (1:50 litter-to-water ratio and four-hour extraction) and recently senesced leaf litter of 41 tropical tree and liana species, we investigated how solubility varies among elements, and whether the solubility of elements could be predicted by litter traits (e.g., lignin, total element concentrations). In addition, we investigated nutrient forms (i.e., inorganic and organic) and ratios in leachate. Water-soluble elements per unit litter mass were strongly predicted by total initial litter element concentrations for potassium (K; r 2 ¼ 0.79), sodium (Na; r 2 ¼ 0.51) and phosphorus (P; r 2 ¼ 0.66), while a significant but weaker positive relationship was found for nitrogen (N; r 2 ¼ 0.36). There was no significant relationship for carbon (C) or calcium (Ca). Element-specific solubility varied markedly. On average 100% of total K, 35% of total P, 28% of total Na, 5% of total N, 4% of total Ca, and 3% of total C were soluble. For soluble P, 90% was inorganic orthophosphate. The high solubility of K, Na, and P as inorganic orthophosphate suggests that these nutrients can become rapidly available to litter microbes with no metabolic cost. Few common predictors of decomposition rates were correlated with element solubility, although soluble C (milligrams per gram of litter) was negatively related to lignin content (r 2 ¼ 0.19; P , 0.004). Solubility of elements was linked within a species: when a species ranked high in the soluble fraction of one element, it also ranked high in the solubility of other elements. Overall nutrient-specific patterns of solubility from recently senesced litter emphasize that litter elements cannot be treated equally in our conceptual and empirical models of decomposition. The relatively high potential solubility of P as orthophosphate from fresh litter advances our understanding of ecological stoichiometric ratios and nutrient bioavailability in tropical forests

    Golimumab 3-year safety update: an analysis of pooled data from the long-term extensions of randomised, double-blind, placebo-controlled trials conducted in patients with rheumatoid arthritis, psoriatic arthritis or ankylosing spondylitis

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    OBJECTIVE: To assess pooled golimumab safety up to year 3 of rheumatoid arthritis (RA), psoriatic arthritis (PsA) and ankylosing spondylitis (AS) trials. METHODS: Golimumab 50 and 100 mg, administered subcutaneously (SC) every 4 weeks (q4wk), were assessed in patients with active RA (methotrexate-naive, methotrexate-experienced and anti-TNF (tumour necrosis factor)-experienced), PsA or AS, despite conventional therapy. Placebo control continued up to week (wk) 24 (wk 52, methotrexate-naive), with early escape at wk 16 (wk 28, methotrexate-naive); subsequently, all patients received golimumab 50 or 100 mg q4wk. After the blinded controlled period, golimumab doses could be adjusted per investigator discretion. Pooled safety analyses reported herein include data from placebo-controlled and uncontrolled study periods up to wk 160. Determinations of incidences/100 patient-years (pt-yrs) for rare events also included RA patients from a phase IIb trial. RESULTS: Across five phase III trials of SC golimumab, 639 patients received placebo and 2226 received golimumab 50 mg (n=1249) and/or 100 mg (n=1501) up to wk 160 (patients may be included in more than one group because non-responders were allowed early escape); 1179 patients were treated for \u3e /=156 weeks. For placebo, golimumab 50 mg and golimumab 100 mg, respective adverse event incidences/100 pt-yrs (95% CIs) up to wk 160 were: 0.28 (0.01 to 1.56), 0.30 (0.12 to 0.62), 0.41 (0.23 to 0.69) for death; 5.31 (3.20 to 8.30), 3.03 (2.36 to 3.82), 5.09 (4.36 to 5.90) for serious infection; 0.00 (0.00 to 0.84), 0.17 (0.05 to 0.44), 0.35 (0.18 to 0.62) for tuberculosis; 0.00 (0.00 to 0.84), 0.13 (0.03 to 0.38), 0.24 (0.10 to 0.46) for opportunistic infection; 0.00 (0.00 to 0.84), 0.00 (0.00 to 0.13), 0.12 (0.03 to 0.30) for demyelination; and 0.00 (0.00 to 0.84), 0.04 (0.00 to 0.24), 0.18 (0.06 to 0.38) for lymphoma. CONCLUSIONS: SC golimumab safety up to 3 years remained consistent with that of other TNF antagonists. Golimumab 100 mg showed numerically higher incidences of serious infections, demyelinating events and lymphoma than 50 mg; safety follow-up up to year 5 continues
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