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The performance of complex and advanced applications of industrial reports requires large computational power. The control system presented in this paper is designed as a multi-microcomputer system. The main purpose of this system is to create a pleasant environment for present and further studies in robotic research. The Advanced Robot Control System (ARC) uses multiple microcomputers based on iAPX 8086 processors. A local bus of each processor allows additional memory and Input/output expansions for increased throughput. Nevertheless, the rising calculation effort for the kinematic and dynamic relations shows the insufficient computing power of standard microprocessors. Therefore a fast floating-point processor has been developed. This Robot Arithmetic Processor (RAP) is built up with bipolar bit-slice components, special arithmetic modules and hardware control mechanisms for on- and off-line diagnostic functions.

The hardware implementation of a cartesian closed-loop control scheme will be presented which allows to define the dynamic behaviour of each degree of freedom of the cartesian coordinate system in a prescribed sense. The control system at joint level is designed by multivariate design methods with an additional feedforward component using the concept of inverse dynamics. To achieve high accuracy for cartesian motions quasi-continuous control mode with cartesian sampling periods of not greater than 5 ms is aimed at. A special purpose processor for calculation of kinematic and dynamic terns is designed and integrated into a multiprocessor architecture. This implementation concept with Robot Arithmetic Processor provides the necessary computational power and allows real-time cartesian closed-loop control which is also essential for cartesian sensory control tasks.

Background Following a first wave in spring and gradual easing of lockdown, Luxembourg experienced an early second epidemic wave of SARS-CoV-2 before the start of summer school holidays on 15th July. This provided the opportunity to investigate the role of school-age children and school settings for transmission. Methods We compared the incidence of SARS-CoV-2 in school-age children, teachers and the general working population in Luxembourg during two epidemic waves: a spring wave from March–April 2020 corresponding to general lockdown with schools being closed and May–July 2020 corresponding to schools being open. We assessed the number of secondary transmissions occurring in schools between May and July 2020 using routine contact tracing data. Results During the first wave in March–April 2020 when schools were closed, the incidence in pupils peaked at 28 per 100,000, while during the second wave in May–July 2020 when schools were open, incidence peaked 100 per 100,000. While incidence of SARS-CoV-2 was higher in adults than in children during the first spring wave, no significant difference was observed during the second wave in early summer. Between May and July 2020, we identified a total of 390 and 34 confirmed COVID-19 cases among 90,150 school-age children and 11,667 teachers, respectively. We further estimate that 179 primary cases caused 49 secondary cases in schools. While some small clusters of mainly student-to-student transmission within the same class were identified, we did not observe any large outbreaks with multiple generations of infection. Conclusions Transmission of SARS-CoV-2 within Luxembourg schools was limited during an early summer epidemic wave in 2020. Precautionary measures including physical distancing as well as easy access to testing, systematic contact tracing appears to have been successful in mitigating transmission within educational settings.

The ground-based augmentation system (GBAS) is the cornerstone for enabling automated landings without the instrument landing system (ILS). Currently, GBAS is evolving to GBAS approach service type-D (GAST-D) for category III landings. This development toward GBAS GAST-D extends GBAS via the use of multiple frequencies (L1/L2 and L5) and the use of multiple global navigation satellite system constellations. GBAS requires correction data to be broadcast to aircraft, which is currently handled via the VHF data broadcast (VDB) datalink. However, VDB has several known shortcomings: 1) low throughput, 2) small area of operation, and 3) no cyber-security measures. In this article, we propose the use of the L-band digital aeronautical communications system (LDACS) for broadcasting GBAS correction data to address these shortcomings. In flight experiments conducted in 2019, we set up an experimental GBAS installation using LDACS. Broadcast data are secured using the timed efficient stream loss-tolerant authentication (TESLA) broadcast authentication protocol. Our results indicate that cryptographically secured GBAS data via LDACS can provide GAST-C and GAST-D services with high availability if cryptographic parameters are chosen appropriately.

An increasing number of people living with multimorbidity may receive suboptimal care since health systems are not well prepared to respond to their complex needs. Identifying which conditions most commonly group together could support better care for patients with multiple diseases. This is particularly critical for conditions that have the most deteriorating effect on quality of life (QoL). The aim of the study was to: 1) identify multimorbidity patterns in Europe and 2) assess their impact on QoL. This was a cross-sectional analysis performed on the Survey of Health, Ageing and Retirement in Europe (SHARE) among adults aged 50+, in eighteen countries (n = 67,179). The Control, Autonomy, Self-Realization and Pleasure (CASP-12v1) scale assessed QoL. Exploratory factor analysis (using 17 conditions) based on tetra-choric correlations, was applied to identify multimorbidity patterns. Associations between patterns and QoL were estimated with multilevel mixed-effects linear regression. The analyses were adjusted for socio-economic, clinical and psycho-social factors, and stratified by sex. Three multimorbidity patterns were found: 1) cardio-metabolic [frequency in men (27.7%); women (25.9%)], 2) psycho-geriatric [1.4%; 0.3%] and 3) mixed [11.7%; 17.4%]. Sample adequacy was confirmed by the Kaiser-Meyer-Olkin test [0.81; 0.84, for men and women, respectively]. The patterns showed slight sex differences. The frequency of all patterns increased with age, while patterns overlapped significantly in the population. The psycho-geriatric pattern had the most deteriorating effect on QoL [-4.5(95%CI:-6.2;-2.8) for men; -5.0(95%CI: -9.5; -0.5) for women]. Recognizing the most common disease patterns may allow more targeted planning and provision of care, including development of clinical guidelines, enhancing collaboration between health professionals, and creation of prevention plans to reduce complications and preserve the best QoL for patients with multimorbidity. Key messages First large population-based study on multimorbidity patterns and their impact on QoL across Europe, using SHARE database. The findings can serve to support better care for multimorbid patients.

Background: The role of schools and children in the transmission of SARS-CoV-2 remains to be determined. Following a first wave in spring and gradual easing of lockdown, Luxembourg experienced an early second epidemic wave before the start of summer school holidays on 15th July. This provided the opportunity to study the role of school-age children and school settings in SARS-CoV-2 transmission. More specifically, we compared the incidence in school-age children, teachers and the general working population, and estimated the number of secondary transmissions occurring at schools using contact tracing data. Findings: While SARS-CoV-2 incidence was much higher in adults aged 20 and above than in children aged 0 to 19 during the first wave in spring, no significant difference was found during the second wave in early summer. The incidence during the second wave was similar for pupils, teachers and the general working population. Based on a total of 424 reported confirmed COVID-19 cases in school-age children and teachers, we estimate that 179 index cases caused 49 secondary transmissions in schools. While some small clusters of mainly student-to-student transmission within the same class were identified, we did not observe any large outbreaks with multiple generations of infection. Interpretation: Transmission of SARS-CoV-2 within Luxembourg schools was limited during the early summer epidemic wave in 2020. Precautionary measures including physical distancing as well as easy access to testing, systematic contact tracing appears to have been successful in mitigating transmission within educational settings. Funding Statement: LV is supported by the Luxembourg National Research Fund grant COVID-19/2020- 1/14701707/REBORN, LM is supported by Luxembourg National Research Fund grant COVID19/14863306/PREVID, PW is supported by the European Research Council (ERC-CoG 863664). Declaration of Interests: No competing interests. Ethics Approval Statement: The Health Directorate has the legal permission to process patient confidential information for national surveillance of communicable diseases in general and contact tracing for the COVID-19 pandemic and individual patient consent is not required.

The increasing air traffic foreseen for the next decades has triggered an extensive modernization of the air traffic management. Specifically, new air traffic services and operational concepts have been defined and shall be supported during all phases of flight by a set of modern digital data links integrated into a single communications network named the Future Communications Infrastructure (FCI). The air-to-air (A2A) component of the FCI, the L-band Digital Aeronautical Communications System (LDACS) A2A mode, is currently in the initial stages of its development. Given that the LDACS A2A mode must be able to operate without any ground or satellite support, the data link must provide means for the aircraft to establish and organize an independent communications ad-hoc network, which imposes a great challenge for the design of the data link and specially for its medium-access control. In this paper, we contribute to the development of the LDACS A2A mode by assessing the performance of an A2A data link based on two different medium-access protocols; ALOHA with and without diversity, and a self-organizing time-division multiple-access (STDMA) scheme. The performance is obtained by simulating the implemented models of both the ALOHA-based and the STDMA-based A2A data link for different design parameters, requirements, and air traffic conditions. The obtained results show that the STDMA-based A2A data link performs better than the ALOHA-based A2A data link in most considered cases, given than the former requires a lower bandwidth than the latter to achieve the desired performance. Based on our analysis, we conclude that STDMA is a better candidate than ALOHA with or without diversity for the medium-access control of the LDACS A2A mode.

In this application paper, the influence of the coolant mantle on the acoustic radiation behaviour of a hybrid drive train is investigated. This was done on an electric machine on an acoustic component test bench. The coolant mass flow around the electric machine stator was varied and then completely drained. The electrical machine remained mechanically unchanged; any variations were made to the feed pumps on the test bench side. Triaxial acceleration sensors are glued to the machine housing and reviewed as evaluation criteria. For the evaluation, the square mean value of all three spatial directions of the glued acceleration sensors was calculated. The evaluation shows that there is no significant acoustic difference between an active stator cooling jacket and a stationary stator cooling jacket. If the stator cooling jacket is pumped out empty so that air remains in it, there is a strong reduction in surface acceleration. The observations are confirmed by analytical literature values. The results presented serve as a basis for further work and developments.