286 research outputs found
Integrated examination of 3D imaging systems for the systematic definition in production technology
In der industriellen Produktion sind Bildverarbeitungssysteme bereits in vielen Bereichen etabliert.
Auch 3D-Bildverarbeitungssysteme werden in der Produktionstechnik fĂŒr die unterschiedlichsten Problemlösungen eingesetzt. Der Einsatzbereich reicht von einfacher QualitĂ€tskontrolle ĂŒber Handlingsaufgaben bis hin zu komplexen Sicherheitsfunkionen in einer Produktionsanlage.
Aufgrund der stetigen Entwicklung und der VielfÀltigkeit der anwendbaren Verfahren in der industriellen Bildverarbeitung stellt die Projektierung von 3D-Bildverarbeitungs- systemen oft eine Herausforderung dar. Die Problematik bei der Integration von 3D-Bildverarbeitungssystemen in der Produktionstechnik besteht oft in der Vielzahl möglicher AnsÀtze, den Aufgabenstellungen der Produktionsautomation mittels Bildverarbeitung gerecht zu werden.
Diese Arbeit beschreibt die Entwicklung einer Methodik zur effizienten Projektierung und Entwicklung von 3D-Bildverarbeitungssystemen im praxisnahen Umfeld des Sondermaschinenbaus.
Es werden zunĂ€chst die auf das System wirkenden EinflussgröĂen bestimmt, die sich aus der Aufgabenstellung, dem Produktionsprozess und dessen Peripherie ergeben. Hiervon ausgehend wird ein methodisches Vorgehen definiert, das es einem Entwickler von Produktionsanlagen ermöglicht, die notwendigen MaĂnahmen zur Realisierung eines effizienten und effektiven 3D-Bildverarbeitungssystems im Verbund mit dem Produktionssystem zu definieren.
In den entworfenen AnsÀtzen im Rahmen dieser Arbeit wird zunÀchst analytisch betrachtet, welche Formalien zur Auswahl bzw. Eingrenzung von bildgebenden Verfahren genutzt werden und wie damit die weitere Evaluierung der Projektierung des Bildverarbeitungssystems ablÀuft.
Im Zuge von Beispielapplikationen wird die Anwendung des vorgestellten Verfahrens explizit verdeutlicht.
Des Weiteren werden in dieser Arbeit objektorientierte Methoden zur Erfassung aller relevanter Merkmale eines 3D-Bildverarbeitungssystems im Bereich der Anlagenautomation und des Sondermaschinenbaus untersucht und angewendet. Dabei werden sowohl produktionstechnische Aspekte als auch spezielle Problematiken der Bildverarbeitung möglichst allgemeingĂŒltig dargestellt. AbschlieĂend wird das Potential dieser Methodik diskutiert und eine EinschĂ€tzung zu Anwendungsmöglichkeiten und zukĂŒnftigen Entwicklungen gegeben.Machine vison systems are suitable in many areas of production in the industrial manufacturing. As well 3D-machine-vision-systems are used as solution for diverse problems in manufacturing engineering.
The area of possible application ranges from simple tasks for quality control or manipulation and handling to complex security relevant issues.
On account of its continued development and the diversity of applicable methods in the field of machine vision, the project planning of 3D machine-vision-application is a challenging task.
The problem with the integration of 3D-vision-systems is the big variety of possibilities to solve problems in plant automation by means of machine-vision methods.
This thesis describes the development of a method for the efficient project planning and design of 3D-machine-vision-systems in the field of special machine construction.
First the influence variables effecting the vision-system are determined, which are arising from the task, the production process and the periphery of the process.
Based on these characteristics a methodical approach is defined. This approach enables developers of production facilities to define the specific measures for implementing an effective and efficient machine-vision-setup, which is well integrated in the production process.
The approach of this thesis is an analytical observation to describe the formalities of the selection of imaging sensors and how this decision is influencing the further project planning and evaluation procedure.
In the context of example application, the application of the approach is presented explicit.
Furthermore, object-oriented methods are investigated regarding their ability to gather all relevant features of a 3D-machine-vision system in the field of plant automation and special machine construction. Both aspects concerning the production and problems of machine vision are described universally. In conclusion, the potential of this approach is discussed and an evaluation of possibilities and further development is given
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Towards Analyzing the Bias of News Recommender Systems Using Sentiment and Stance Detection
News recommender systems are used by online news providers to alleviate information overload and to provide personalized content to users. However, algorithmic news curation has been hypothesized to create filter bubbles and to intensify users' selective exposure, potentially increasing their vulnerability to polarized opinions and fake news. In this paper, we show how information on news items' stance and sentiment can be utilized to analyze and quantify the extent to which recommender systems suffer from biases. To that end, we have annotated a German news corpus on the topic of migration using stance detection and sentiment analysis. In an experimental evaluation with four different recommender systems, our results show a slight tendency of all four models for recommending articles with negative sentiments and stances against the topic of refugees and migration. Moreover, we observed a positive correlation between the sentiment and stance bias of the text-based recommenders and the preexisting user bias, which indicates that these systems amplify users' opinions and decrease the diversity of recommended news. The knowledge-aware model appears to be the least prone to such biases, at the cost of predictive accuracy
A high-flux BEC source for mobile atom interferometers
Quantum sensors based on coherent matter-waves are precise measurement
devices whose ultimate accuracy is achieved with Bose-Einstein condensates
(BEC) in extended free fall. This is ideally realized in microgravity
environments such as drop towers, ballistic rockets and space platforms.
However, the transition from lab-based BEC machines to robust and mobile
sources with comparable performance is a challenging endeavor. Here we report
on the realization of a miniaturized setup, generating a flux of quantum degenerate Rb atoms every 1.6s. Ensembles of atoms can be produced at a 1Hz rate. This is achieved by loading a
cold atomic beam directly into a multi-layer atom chip that is designed for
efficient transfer from laser-cooled to magnetically trapped clouds. The
attained flux of degenerate atoms is on par with current lab-based BEC
experiments while offering significantly higher repetition rates. Additionally,
the flux is approaching those of current interferometers employing Raman-type
velocity selection of laser-cooled atoms. The compact and robust design allows
for mobile operation in a variety of demanding environments and paves the way
for transportable high-precision quantum sensors.Comment: 22 pages, 6 figure
NeMig -- A Bilingual News Collection and Knowledge Graph about Migration
News recommendation plays a critical role in shaping the public's worldviews
through the way in which it filters and disseminates information about
different topics. Given the crucial impact that media plays in opinion
formation, especially for sensitive topics, understanding the effects of
personalized recommendation beyond accuracy has become essential in today's
digital society. In this work, we present NeMig, a bilingual news collection on
the topic of migration, and corresponding rich user data. In comparison to
existing news recommendation datasets, which comprise a large variety of
monolingual news, NeMig covers articles on a single controversial topic,
published in both Germany and the US. We annotate the sentiment polarization of
the articles and the political leanings of the media outlets, in addition to
extracting subtopics and named entities disambiguated through Wikidata. These
features can be used to analyze the effects of algorithmic news curation beyond
accuracy-based performance, such as recommender biases and the creation of
filter bubbles. We construct domain-specific knowledge graphs from the news
text and metadata, thus encoding knowledge-level connections between articles.
Importantly, while existing datasets include only click behavior, we collect
user socio-demographic and political information in addition to explicit click
feedback. We demonstrate the utility of NeMig through experiments on the tasks
of news recommenders benchmarking, analysis of biases in recommenders, and news
trends analysis. NeMig aims to provide a useful resource for the news
recommendation community and to foster interdisciplinary research into the
multidimensional effects of algorithmic news curation.Comment: Accepted at the 11th International Workshop on News Recommendation
and Analytics (INRA 2023) in conjunction with ACM RecSys 202
Status of the GEO 600 squeezed-light laser
In the course of the high-frequency upgrade of GEO 600, its optical
configuration was extended by a squeezed-light laser [1]. Recently, a
non-classically enhanced measurement sensitivity of GEO 600 was reported [2].
In this paper, a characterization of the squeezed-light laser is presented.
Thereupon, the status of the integration into GEO 600 is reviewed, focussing on
the sources of optical loss limiting the shot noise reduction by squeezing at
the moment. Finally, the possibilities for a future loss reduction are
discussed.Comment: Proceeding of the 9th Edoardo Amaldi Conference on Gravitational
Wave
Michelson interferometer with diffractively-coupled arm resonators in second-order Littrow configuration
Michelson-type laser-interferometric gravitational-wave (GW) observatories
employ very high light powers as well as transmissively- coupled Fabry-Perot
arm resonators in order to realize high measurement sensitivities. Due to the
absorption in the transmissive optics, high powers lead to thermal lensing and
hence to thermal distortions of the laser beam profile, which sets a limit on
the maximal light power employable in GW observatories. Here, we propose and
realize a Michelson-type laser interferometer with arm resonators whose
coupling components are all-reflective second-order Littrow gratings. In
principle such gratings allow high finesse values of the resonators but avoid
bulk transmission of the laser light and thus the corresponding thermal beam
distortion. The gratings used have three diffraction orders, which leads to the
creation of a second signal port. We theoretically analyze the signal response
of the proposed topology and show that it is equivalent to a conventional
Michelson-type interferometer. In our proof-of-principle experiment we
generated phase-modulation signals inside the arm resonators and detected them
simultaneously at the two signal ports. The sum signal was shown to be
equivalent to a single-output-port Michelson interferometer with
transmissively-coupled arm cavities, taking into account optical loss. The
proposed and demonstrated topology is a possible approach for future
all-reflective GW observatory designs
Long-term stable squeezed vacuum state of light for gravitational wave detectors
Currently, the German/British gravitational wave detector GEO600 is being
upgraded in course of the GEO-HF program. One part of this upgrade consists of
the integration of a squeezed light laser to nonclassically improve the
detection sensitivity at frequencies where the instrument is limited by shot
noise. This has been achieved recently [1]. The permanent employment of
squeezed light in gravitational wave observatories requires a long-term
stability of the generated squeezed state. In this paper, we discuss an
unwanted mechanism that can lead to a varying squeezing factor along with a
changing phase of the squeezed field. We present an extension of the
implemented coherent control scheme [2] that allowed an increase in the
long-term stability of the GEO600 squeezed light laser. With it, a quantum
noise reduction by more than 9 dB in the frequency band of 10 Hz - 10 kHz was
observed over up to 20 hours with a duty cycle of more than 99%
Specific Varicella-Related Complications and Their Decrease in Hospitalized Children after the Introduction of General Varicella Vaccination: Results from a Multicenter Pediatric Hospital Surveillance Study in Bavaria (Germany)
Hagemann C, KrÀmer A, Grote V, Liese JG, Streng A. Specific Varicella-Related Complications and Their Decrease in Hospitalized Children after the Introduction of General Varicella Vaccination: Results from a Multicenter Pediatric Hospital Surveillance Study in Bavaria (Germany). Infectious Diseases and Therapy. 2019;8(4):1-15.Background
Universal varicella vaccination (UVV) for children introduced in Germany in 2004 resulted in a significant overall decline of varicella-related hospitalizations (VRHs). We investigated the incidence of specific types of varicella-related complications (VRCs) in hospitalized children and the impact of UVV on VRCs during the first 7 years of UVV.
Methods
Childrenâ<â17 years of age hospitalized with an ICD-10-based (International Classification of Diseases, 10th Revision) discharge diagnosis of varicella were identified as VRH in pediatric hospitals in Bavaria by annual standardized data queries of the hospital databases (2005â2011). For each VRH, the hospitals reported basic demographic data, duration of hospital stay, all diagnostic and procedural codes, and outcome. VRCs were reported overall, per year, and by immune status. Complication rates were calculated as mean number per complication category per hospital and per year; VRC trends over time were assessed by linear regression.
Results
Between 78% (2005) and 61% (2011) of Bavarian hospitals participated and reported a total of 1263 VRHs. Specific VRCs were reported in 954 (76%) children. Complication rates per hospital and year decreased from 6.7 [95% confidence interval (CI): 5.1â8.3] in 2005 to 1.5 (95% CI: 0.8â2.3) in 2011, with the strongest reduction of 90% in childrenâ<â5 years of age from 5.3 (95% CI: 4.0â6.6) in 2005 to 0.5 (95% CI: 0.1â0.9) in 2011. Significant decreases were observed for children with upper respiratory tract (URT, by 97%), lower respiratory tract (LRT, by 90%), skin (by 81%), gastrointestinal (by 78%), and neurologic (by 65%) VRCs. Forty-eight children with VRCs were immunocompromised; their annual rate decreased by 87%.
Discussion
Corresponding to increasing varicella vaccination coverage in the population, the incidence of VRC decreased by 77% from 2005 to 2011, with the most substantial decrease in the target group for UVV.
Conclusion
Within 7 years, UVV in Germany led to a decrease of about 77% of all types of VRCs, with the highest reductions observed for VRCs of the respiratory tract
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