156 research outputs found
Boundary conditions for the application of machine learning based monitoring systems for supervised anomaly detection in machining
Monitoring systems may contribute increasing the availability of machine tools and detecting process deviations in time. In the past, machine learning has been used to solve a variety of monitoring problems in machining. However, boundary conditions for the assessment of the principal applicability of machine learning approaches for supervised anomaly detection in machining have not been exhaustively described in the literature. In this paper, objectives as well as deficits of literature approaches are identified and influencing factors on the monitoring quality are described. As a result, we derive boundary conditions and discuss challenges for successful implementation of machine learning based monitoring systems for supervised anomaly detection in industrial practice
Data-based ensemble approach for semi-supervised anomaly detection in machine tool condition monitoring
Data-based methods are capable to monitor machine components. Approaches for semi-supervised anomaly detection are trained using sensor data that describe the normal state of machine components. Thus, such approaches are interesting for industrial practice, since sensor data do not have to be labeled in a time-consuming and costly way. In this work, an ensemble approach for semi-supervised anomaly detection is used to detect anomalies. It is shown that the ensemble approach is suitable for condition monitoring of ball screws. For the evaluation of the approach, a data set of a regular test cycle of a ball screw from automotive industry is used
Combinatorial hydrogel library enables identification of materials that mitigate the foreign body response in primates
The foreign body response is an immune-mediated reaction that can lead to the failure of implanted medical devices and discomfort for the recipient. There is a critical need for biomaterials that overcome this key challenge in the development of medical devices. Here we use a combinatorial approach for covalent chemical modification to generate a large library of variants of one of the most widely used hydrogel biomaterials, alginate. We evaluated the materials in vivo and identified three triazole-containing analogs that substantially reduce foreign body reactions in both rodents and, for at least 6 months, in non-human primates. The distribution of the triazole modification creates a unique hydrogel surface that inhibits recognition by macrophages and fibrous deposition. In addition to the utility of the compounds reported here, our approach may enable the discovery of other materials that mitigate the foreign body response.Leona M. and Harry B. Helmsley Charitable Trust (3-SRA-2014-285-M-R)United States. National Institutes of Health (EB000244)United States. National Institutes of Health (EB000351)United States. National Institutes of Health (DE013023)United States. National Institutes of Health (CA151884)United States. National Institutes of Health (P41EB015871-27)National Cancer Institute (U.S.) (P30-CA14051
Selective Processing of Multiple Features in the Human Brain: Effects of Feature Type and Salience
Identifying targets in a stream of items at a given constant spatial location relies on selection of aspects such as color, shape, or texture. Such attended (target) features of a stimulus elicit a negative-going event-related brain potential (ERP), termed Selection Negativity (SN), which has been used as an index of selective feature processing. In two experiments, participants viewed a series of Gabor patches in which targets were defined as a specific combination of color, orientation, and shape. Distracters were composed of different combinations of color, orientation, and shape of the target stimulus. This design allows comparisons of items with and without specific target features. Consistent with previous ERP research, SN deflections extended between 160–300 ms. Data from the subsequent P3 component (300–450 ms post-stimulus) were also examined, and were regarded as an index of target processing. In Experiment A, predominant effects of target color on SN and P3 amplitudes were found, along with smaller ERP differences in response to variations of orientation and shape. Manipulating color to be less salient while enhancing the saliency of the orientation of the Gabor patch (Experiment B) led to delayed color selection and enhanced orientation selection. Topographical analyses suggested that the location of SN on the scalp reliably varies with the nature of the to-be-attended feature. No interference of non-target features on the SN was observed. These results suggest that target feature selection operates by means of electrocortical facilitation of feature-specific sensory processes, and that selective electrocortical facilitation is more effective when stimulus saliency is heightened
Technological Pathways to Produce Compressed and Highly Pure Hydrogen from Solar Power
Hydrogen H2 produced from renewables will have a growing impact on the global energy dynamics towards sustainable and carbon neutral standards. The share of green H2 is still too low to meet the net zero target, while the demand for high quality hydrogen continues to rise. These factors amplify the need for economically viable H2 generation technologies. The present article aims at evaluating the existing technologies for high quality H2 production based on solar energy. Technologies such as water electrolysis, photoelectrochemical and solar thermochemical water splitting, liquid metal reactors and plasma conversion utilize solar power directly or indirectly as carbon neutral electrons and are reviewed from the perspective of their current development level, technical limitations and future potentia
Convergent evolution of highly reduced fruiting bodies in Pezizomycotina suggests key adaptations to the bee habitat
BACKGROUND: Among the understudied fungi found in nature are those living in close association with social and solitary bees. The bee-specialist genera Bettsia, Ascosphaera and Eremascus are remarkable not only for their specialized niche but also for their simple fruiting bodies or ascocarps, which are morphologically anomalous in Pezizomycotina. Bettsia and Ascosphaera are characterized by a unicellular cyst-like cleistothecium known as a spore cyst, while Eremascus is characterized by completely naked asci, or asci not formed within a protective ascocarp. Before molecular phylogenetics the placement of these genera within Pezizomycotina remained tentative; morphological characters were misleading because they do not produce multicellular ascocarps, a defining character of Pezizomycotina. Because of their unique fruiting bodies, the close relationship of these bee-specialist fungi and their monophyly appeared certain. However, recent molecular studies have shown that Bettsia is not closely related to Ascosphaera. In this study, I isolated the very rare fungus Eremascus fertilis (Ascomycota, Pezizomycotina) from the bee bread of honey bees. These isolates represent the second report of E. fertilis both in nature and in the honey bee hive. To establish the systematic position of E. fertilis and Bettsia alvei, I performed phylogenetic analyses of nuclear ribosomal LSU + SSU DNA sequences from these species and 63 additional ascomycetes. RESULTS: The phylogenetic analyses revealed that Eremascus is not monophyletic. Eremascus albus is closely related to Ascosphaera in Eurotiomycetes while E. fertilis belongs in Myxotrichaceae, a putative member of Leotiomycetes. Bettsia is not closely related to Ascosphaera and like E. fertilis apparently belongs in Leotiomycetes. These results indicate that both the naked ascus and spore cyst evolved twice in the Pezizomycotina and in distantly related lineages. The new genus Skoua is described to accommodate E. fertilis. CONCLUSIONS: The naked ascus and spore cyst are both shown to have evolved convergently within the bee habitat. The convergent evolution of these unusual ascocarps is hypothesized to be adaptive for bee-mediated dispersal. Elucidating the dispersal strategies of these fungal symbionts contributes to our understanding of their interaction with bees and provides insight into the factors which potentially drive the evolution of reduced ascocarps in Pezizomycotina. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12862-015-0401-6) contains supplementary material, which is available to authorized users
Stratigraphy and structure of the Acker-Bruchberg zone and the Kellerwald region, Germany
The age of Lossen's Hauptkieselschiefer and of the colored schists of the southern Harz syncline
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