Aiming at self-calibration of terrestrial laser scanners using only one single object and one single scan

When using terrestrial laser scanners for high quality analyses, calibrating the laser scanner is crucial due to unavoidable misconstruction of the instrument leading to systematic errors. Consequently, the development of calibration fields for laser scanner self-calibration is widespread in the literature. However, these calibration fields altogether suffer from the fact that the calibration parameters are estimated by analyzing the parameter differences of a limited number of substitute objects (targets or planes) scanned from different stations. This study investigates the potential of self-calibrating a laser scanner by scanning one single object with one single scan. This concept is new since it uses the deviation of each sampling point to the scanned object for calibration. Its applicability rests upon the integration of model knowledge that is used to parameterize the scanned object. Results show that this calibration approach is feasible leading to improved surface approximations. However, it makes great demands on the functional model of the calibration parameters, the stochastic model of the adjustment, the scanned object and the scanning geometry. Hence, to gain constant and physically interpretable calibration parameters, further improvement especially regarding functional and stochastic model is demanded

Automated Fusion System Design and Adaptation Implementation

This published prototype is a JAVA-based implementation of the automated fusion system design proposed in [FMH+17]. The implementation orchestrates a distributed information fusion system, i.e., it identifies features and attribute supported by the system. The automated orchestration is carried out at a central device called system manager. Basic elements of the fusion system are intelligent sensors. Intelligent sensors monitor a system using elementary sensors (e.g., temperature sensors or acoustic sensors) [MDL+16, FML16]. The sensor signals of all intelligent sensors are gathered and fused to evaluate the condition (i.e., health) of the monitored system. An intelligent sensor is additionally equipped with processor units, memory, and communication interfaces. It is self-adaptable and self-aware. An intelligent sensor hosts a semantic self-description stating available elementary sensors and algorithms. Algorithms are used to extract certain features from sensor signals. This implementation uses the Raspberry Pi 3B as platform for intelligent sensors. The Raspberry Pis 3B supports several interfaces to read multiple elementary sensor signals. This implementation reads sensor signals via the Serial Peripheral Interface (SPI). Communication between intelligent sensors uses the Raspberry Pi’s Ethernet interface. All communication for the organisation and configuration of the fusion system uses TCP/IP. Process data (sensor signals and features) are communicated via an Industrial Ethernet in real-time. The process data communication is not part of this publication. The automated fusion system design is structured into the following four phases: Discovery: The system manager searches for available intelligent sensors. The discovery phase is carried out continuously independent of the other three phases. If a new intelligent sensor is discovered, the knowledge building phase is triggered. Knowledge Building: Semantic information (self-description of intelligent sensors) is transferred to a knowledge base at the system manager. Orchestration: The system manager carries out the fusion system configuration automatically. Operation: All intelligent sensors periodically send their sensor signals and features to the system manager using a real-time Ethernet protocol. Discovery of intelligent sensors and transfer of semantic information is implemented using the Open Platform Communication Unified Architecture (OPC UA). OPC UA offers a Local Discovery Server (LDS), which exposes available OPC UA servers in a local network. As soon as the system manager has discovered an intelligent sensor, the semantic self-description is collected and stored in the system manager’s knowledge base. Then, the fusion system is orchestrated using a rule-based system. The orchestration engine identifies based on available sensors and algorithms features and different kinds of attributes (physical, module, functional,quality). For details about the orchestration process and the rule-based system the reader is referred to the corresponding journal article [FMH+17]. The last step in the orchestration phase is the creation of an configuration file for the real-time communication. This configuration file is used to determine the layout of the real-time Ethernet communication network. The source code is included in the ZIP file of this upload. The accompanying PDF contains a description on how to compile and execute the implementation. [FMH+17] FRITZE, Alexander ; MÖNKS, Uwe ; HOLST, Christoph-Alexander ; LOHWEG, Volker: An Approach to Automated Fusion System Design and Adaptation. In: Sensors 17 (2017), Nr. 3, 601. http://dx.doi.org/10.3390/s17030601. – DOI 10.3390/s17030601 [FML16] FRITZE, Alexander ; MÖNKS, Uwe ; LOHWEG, Volker: A Support System for Sensor and Information Fusion System Design. In: 3rd International Conference on System-Integrated Intelligence - New Challenges for Product and Production Engineering, Paderborn, Germany, 2016 [MDL+16] MÖNKS, Uwe ; DÖRKSEN, Helene ; LOHWEG, Volker ; HÜBNER, Michael: Information Fusion of Conflicting Input Data. In: Sensors (Basel, Switzerland) 16 (2016), Nr. 11. http://dx.doi.org/10.3390/s16111798. – DOI 10.3390/s16111798. – ISSN 1424–822

Biased and unbiased estimates based on laser scans of surfaces with unknown deformations

The estimates based on laser scans of surfaces with unknown deformations are biased and not reproducible when changing the scanning geometry. While the existence of a bias is only disadvantageous at some applications, non-reproducible estimates are never desired. Hence, this varying bias and its origin need to be investigated – since this situation has not been examined sufficiently in the literature. Analyzing this situation, the dependence of the estimation on the network configuration is highlighted: the network configuration – studied similarly to geodetic networks – rules about the impact of the deformation. As pointed out, this impact can be altered by manipulating the network configuration. Therefore, several strategies are proposed. These include manipulations of the least-squares adjustment as well as robust estimation. It is revealed that the reproducibility of the estimates can indeed be significantly increased by some of the proposed least-squares manipulations. However, the bias can only be significantly reduced by robust estimation

Keypoint-based deformation monitoring using a terrestrial laser scanner from a single station: Case study of a bridge pier

[EN] Terrestrial laser scanners (TLSs) offer a possibility for more automated and efficient deformation monitoring of civil engineering structures with higher spatial resolution than standard methods, as well as without the necessity of permanently installing the monitoring equipment. In such applications, scanners are usually placed so that the lines of sight are roughly aligned with the main directions of the expected deformations, and the deformations are estimated from point cloud differences between multiple epochs. This allows high sensitivity in the direction of the surface normal, but deformations along the surface are often undetected or hard to precisely quantify. In this work, we propose an algorithm based on the detection and matching of keypoints identified within TLS intensity images. This enables precise quantification of deformations along the scanned surfaces. We also present the application of the algorithm for monitoring a bridge pier of the Hochmoselbrücke in Germany, as a case study. Deformations up to about 4 cm due to thermal expansion and bending of the pier were successfully detected from scans taken throughout the day from a single location, up to 180 m from the monitored surfaces. The results agreed within a few millimeters to independent monitoring using state-of-the-art processing of TLS point clouds obtained from a different location and using a different type/brand of instrument. The newly proposed algorithm can either be used to complement existing TLS-based deformation analysis methods by adding sensitivity in certain directions, or it can be valuable as a standalone solution.Medic, T.; Ruttner, P.; Holst, C.; Wieser, A. (2023). Keypoint-based deformation monitoring using a terrestrial laser scanner from a single station: Case study of a bridge pier. En 5th Joint International Symposium on Deformation Monitoring (JISDM 2022). Editorial Universitat Politècnica de València. 167-175. https://doi.org/10.4995/JISDM2022.2022.1381216717

EURL-FA Control Proficiency test report: Determination of authorised coccidiostats in compound feed

The European Union Reference Laboratory for Feed Additives (EURL-FA), hosted by the Joint Research Centre (JRC), a Directorate General of the European Commission, has been mandated by the Directorate General for Health and Food Safety (DG SANTE) to organise a proficiency test (PT) among appointed National Reference Laboratories (NRLs) in the frame of its control activities (according to the Regulation (EC) No 882/2004 [1]). The aim of this PT was to assess the capacity of the NRLs to correctly determine selected authorised coccidiostats added to feed matrices at realistic authorised levels and at cross-contamination levels. Thirty-six European National and Official Control laboratories were invited and twenty-nine laboratories registered to the 2017 PT exercise. Twenty-five of the registered laboratories reported results for the analyses. The test items used in this exercise were produced by the JRC. Purchased commercial poultry compound feed, tested by the EURL-FA Control as being blank for the target analytes, was milled and ground and then spiked with the required coccidiostat standard solution or with the relevant authorised feed additive. The first item was spiked with a standard solution containing monensin, narasin and diclazuril, at cross-contamination level (MAT 1). The second test item (MAT 2) was spiked with an authorised feed additive Maxiban®, containing narasin (narasin AL) and nicarbazin, at additive level. MAT 1 and MAT 2 were subsequently homogenised and distributed in glass bottles. All bottles were labelled ensuring a random number encoding and dispatched to all registered participants on 27 June 2017. Laboratories were informed of the composition of the test material regarding the composition in coccidiostats for MAT 2 and had therefore only to quantify the content. For MAT 1 the laboratories had to screen for the presence of all 11 authorised coccidiostats and to quantify the detected ones. The assigned values (xpt) for the mass content of monensin, diclazuril and narasin in MAT 1 were calculated from the formulation as recommended by the IUPAC harmonized protocol [2]. The uncertainties for the assigned values (u(xpt)) were calculated according to the ISO Guide for the Expression of Uncertainty in Measurement (GUM) [3]. For narasin and nicarbazin in MAT 2, no assigned value was set since the criterion for sufficient homogeneity could not be met. Participants were invited to report their measurement uncertainties. This was done by twenty-three out of twenty-five reporting participants for monensin and narasin, seventeen for diclazuril, and twenty for narasin AL and nicarbazin. Laboratory results were rated using z and ζ (zeta) scores in accordance with ISO 13528:2015 [4]. The relative standard deviation for proficiency assessment (σpt) for each assigned value was calculated using the relevant Horwitz [5] or modified Horwitz equation [6]. The z scores obtained were considered satisfactory if their absolute values were equal to or below 2. The outcome of this PT exercise is mixed; the percentage of satisfactory results reported by the laboratories for MAT 1 is 88%, 80% and 57% for monensin, narasin and diclazuril respectively. For narasin AL and nicarbazin in MAT 2, no scoring was computed but the data reported by the laboratories were examined. In general, there was good agreement among the values of mass content of narasin and nicarbazin reported results. The laboratories also reported qualitative results as regards the presence of one or more of the other authorised coccidiostats. On the whole, the rate of false positive results was of 4% for robenidine, lasalocid, salinomycin and maduramicin; 5% for nicarbazin; 8% for decoquinate; and 0% for all the others. Two laboratories did not quantify diclazuril in MAT 1 while stating a limit of quantification of the method used lower than the assigned value, leading to a false negative rate of 9% for this analyte. One laboratory could not quantify diclazuril in MAT 1 due to the lack of sensitivity of the method used.JRC.F.5-Food and Feed Complianc

Leiharbeit in Thüringen: eine Bestandsaufnahme

Einleitend wird die Leiharbeit als eine prekäre Beschäftigungsform dargestellt. Vor diesem Hintergrund werden die allgemeine Entwicklung der Leiharbeit und die aktuellen Entwicklungstrends in den Einsatzbranchen analysiert. Anschließend werden Beschäftigungsdauer und Überlassungszeitraum, die arbeitsmarktpolitische Effekte der Leiharbeit, die Lohn- und Gehaltsstruktur der Leiharbeitsbranche, das Prekaritätsrisiko der Leiharbeit sowie die Tarifverträge in der Leiharbeit untersucht. Die Mitbestimmung und die Weiterbildung in der Leiharbeit stellen eigene Akzente der Studie dar. Es wird argumentiert, dass flexibilitätspolitisch die Reform ein voller Erfolg gewesen zu sein scheint. Einsatzbetriebe aus nahezu allen Branchen greifen auf Leiharbeit als Flexibilisierungsinstrument zurück - sei es um kurzfristige Auftragsspitzen abzuwickeln oder um kurzfristigen Personalausfall auszugleichen. Die arbeitsmarktpolitische Bilanz fällt hingegen weitaus weniger eindeutig aus. Den vielen in der Leiharbeitsbranche geschaffenen Arbeitsplätzen steht das hohe Armuts- und Prekaritätsrisiko der Leiharbeit gegenüber. Die Entgelte eines erheblichen Teils der Leiharbeiter liegen unterhalb der Armutsgefährdungsschwelle für alleinstehende Personen, die Unsicherheit ihres Beschäftigungsverhältnisses macht die Leiharbeiter - allen voran die gering qualifizierten unter ihnen - verwundbar. Zudem deutet der überdurchschnittlich hohe Anteil der für Hilfstätigkeiten überlassenen Leiharbeitskräfte in Thüringen in Verbindung mit dem parallelen Anstieg des Anteils dieser Berufsgruppe an der Gesamtbeschäftigung darauf hin, dass heimische Betriebe nicht nur reguläre Beschäftigung mit Leiharbeit ersetzen, sondern zugleich Facharbeitsplätze missbräuchlich als Hilfstätigkeiten klassifiziert werden, um die großen Differenzen der unterschiedlichen tarifvertraglichen Entgeltniveaus auszunutzen. Ermöglicht werden derartige Praktiken durch die hohe Verfügbarkeit arbeitsloser Facharbeiter in vielen Regionen des Landes. Es müssen Maßnahmen in Angriff genommen werden, um das Armuts- und Prekaritätsrisiko der Leiharbeit zu verringern und die Missbrauchsmöglichkeiten einzuschränken - ohne die flexibilitätspolitischen Vorteile der Leiharbeit zu opfern. (ICF2

EURL-FA Control Proficiency Test Report: Determination of the mass fraction of the total cobalt in compound feed for rabbits

The European Union Reference Laboratory for Feed Additive Control (EURL-FA Control) organised a proficiency test (EURL-FAC 2017-2) for the determination of the mass fraction of total cobalt in compound feed, to support the Commission Implementing Regulation (EU) No 131/2014 concerning the authorisation of various cobalt(II) compounds as feed additives. This proficiency test was open to National Reference Laboratories (NRLs) and official feed control laboratories (OCLs). The material used as test item was a commercially available compound feed for rabbits (containing the coated granulated cobalt (II) carbonate, 3b304 ) which, after appropriate processing, was bottled, labelled and dispatched to participants on June 21, 2017. The homogeneity and stability of the test item were evaluated and the assigned values were derived from the results reported by the selected expert laboratories. Twenty one NRLs and two OCLs from 21 countries - representing EU Member States and Norway - registered to the exercise and reported results at the end of August 2017. Laboratory results were rated using z' and zeta scores in accordance with ISO 13528:2015. A relative standard deviation for proficiency assessment (σpt) of 16 % of the assigned value was set according to the modified Horwitz equation. Twenty (out of 23) laboratories reported satisfactory results (according to the z' score). This confirms the ability of most NRLs in monitoring maximum levels set by the Commission Implementing Regulation (EU) No 131/2014 in this type of animal feed. The majority (74 %) of the participating laboratories provided realistic estimates of their measurement uncertainties.JRC.F.5-Food and Feed Complianc

Community Reference Laboratory for Feed Additives Authorisation: Annual Report 2006

The objective of this report is to present the activities of the Community Reference Laboratory for Feed Additives Authorisation in 2006 (CRL-FAA). The report shows that besides the evaluation of dossiers, the CRL-FAA carried out many other tasks. Important additional matters were the successful accreditation of the laboratory according to ISO 17025, the support of the European Commission regarding the drafting of the new guidelines for the applicants, further improvement of informatics tools and the organisation of two workshops to discuss these topics with the National Reference Laboratory.JRC.D.8-Food safety and qualit

Physical and mental recovery after aortic valve surgery in non-elderly patients: native valve-preserving surgery vs. prosthetic valve replacement

Background: Exercise capacity and patient-reported outcomes are increasingly considered crucial following aortic valve (AV) surgery in non-elderly adults. We aimed to prospectively evaluate the effect of native valve preservation compared with prosthetic valve replacement. Methods: From October 2017 to August 2020, 100 consecutive non-elderly patients undergoing surgery for severe AV disease were included. Exercise capacity and patient-reported outcomes were evaluated upon admission, and 3 months and 1 year postoperatively. Results: In total, 72 patients underwent native valve-preserving procedures (AV repair or Ross procedure, NV group), and 28 patients, prosthetic valve replacement (PV group). Native valve preservation was associated with an increased risk of reoperation (weighted hazard ratio: 10.57 (95% CI: 1.24–90.01), p = 0.031). The estimated average treatment effect on six-minute walking distance in NV patients at 1 year was positive, but not significant (35.64 m; 95% CI: −17.03–88.30, adj. p = 0.554). The postoperative physical and mental quality of life was comparable in both groups. Peak oxygen consumption and work rate were better at all assessment time points in NV patients. Marked longitudinal improvements in walking distance (NV, +47 m (adj. p < 0.001); PV, +25 m (adj. p = 0.004)) and physical (NV, +7 points (adj. p = 0.023); PV, +10 points (adj. p = 0.005)) and mental quality of life (NV, +7 points (adj. p < 0.001); PV, +5 points (adj. p = 0.058)) from the preoperative period to the 1-year follow-up were observed. At 1 year, there was a tendency of more NV patients reaching reference values of walking distance. Conclusions: Despite the increased risk of reoperation, physical and mental performance markedly improved after native valve-preserving surgery and was comparable to that after prosthetic aortic valve replacement