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Electrical circuits are present in a variety of technologies, making their design an important part of computer aided engineering. The growing number of parameters that affect the final design leads to a need for new approaches to quantify their impact. Machine learning may play a key role in this regard; however, current approaches often make suboptimal use of existing knowledge about the system at hand. In terms of circuits, their description via modified nodal analysis is well‐understood. This particular formulation leads to systems of differential‐algebraic equations (DAEs), which bring with them a number of peculiarities, for example, hidden constraints that the solution needs to fulfill. We use the recently introduced dissection index that can decouple a given system of DAEs into ordinary differential equations, only depending on differential variables, and purely algebraic equations, that describe the relations between differential and algebraic variables. The idea is to then only learn the differential variables and reconstruct the algebraic ones using the relations from the decoupling. This approach guarantees that the algebraic constraints are fulfilled up to the accuracy of the nonlinear system solver, and it may also reduce the learning effort as only the differential variables need to be learned. [ABSTRACT FROM AUTHOR]

The consequences of new airspace entrants, such as novel aircraft concepts with innovative propulsion systems, on air traffic management operations need to be carefully identified. This paper aims to assess the impact of future aircraft with different performance envelopes on the European air traffic network from a flow-based perspective. The underlying approach assumes that all certification-related questions concerning airworthiness have been resolved and do not take into account any economic factors related to airline operations. For example, for an innovative propulsion system, a short range all-electric aircraft is considered in this study. Aircraft trajectory calculations are based on the dataset of base of aircraft data (BADA), which are developed and maintained by EUROCONTROL. The new design concept is integrated into BADA as well, resulting in a new set of coefficients for the all-electric aircraft. In addition to the adjusted parameters which affect airborne performances, ground-related aspects are also taken into account. This includes assumptions on operational procedures, charging capacities and adaptions in infrastructure. Investigations are carried out at the trajectory level as well as at the airport and the entire network. [ABSTRACT FROM AUTHOR]

This paper presents a concept of a fast-time gate-to-gate simulation environment. The implementation is divided into an air traffic part that uses BADA performance parameters and a simulation of ground processes. The main objective of the flow-based hybrid simulation environment is to cover commercial European air traffic, in order to investigate network-related effects when exposed to disturbances. Based on historic traffic scenarios, the hybrid simulation platform enables the investigation of the local and global effects of a variety of disruptions. With respect to current flow-based models, it is intended to gain better insights into the underlying interdependencies by modelling higher levels of detail for selected parts, whilst covering the whole European air traffic network. After a validation and first calibration of the approach, Monte Carlo simulations, based on flight plans, are performed as proof of concept. This aims to illustrate the local effects of network-wide disturbances and is applied by means of stochastic influences of ground processes, gained from real operational data. [ABSTRACT FROM AUTHOR]

The turnaround process constitutes an important part of the air transportation system. Airports often represent bottlenecks in air traffic management (ATM), thus operations related to the preparation of the aircraft for the next flight leg have to be executed smoothly and in a timely manner. The ATM significantly depends on a reliable turnaround process. Future paradigm changes with respect to airplane energy sources, aircraft design or propulsion concepts will also influence the airport layout. As a consequence, operational processes associated with the turnaround will be affected. Airlines aim for efficient and timely turnaround operations that are correlated with higher profits. This case study discusses an approach to investigate a new aircraft design with respect to the implications on the turnaround. The boarding process, as part of the turnaround, serves as an example to evaluate the consequences of new design concepts. This study is part of an interdisciplinary research to investigate future energy, propulsion and designs concepts and their implications on the whole ATM system. Due to these new concepts, several processes of the turnaround will be affected. For example, new energy storage concepts will influence the fueling process on the aircraft itself or might lead to a new infrastructure at the airport. This paper aims to evaluate the applied methodology in the case of a new boarding process, due to a new aircraft design, by means of a generic example. An agent-based boarding simulation is applied to assess passenger behavior during boarding, particularly with regard to cabin layout and seat configuration. The results of the generic boarding simulation are integrated into a simplified, deterministic and generic simulation of the turnaround process. This was done to assess the proposed framework for future investigations which on the one hand address the ATM system holistically and on the other, incorporate additional or adapted processes of the turnaround. [ABSTRACT FROM AUTHOR]

Aircraft emissions represent a relevant amount of human induced CO2. Globally, up to 2.5 per cent of such emissions stem from the aviation industry. In order to investigate the effects within the atmosphere, realistic flight profiles are necessary to provide quantitatively tangible values of emissions. The flight profiles and the according fuel consumption can be calculated by using waypoints from flight plans and Base of Aircraft Data (BADA). This paper presents an approach to refine the fuel consumption by integrating the passenger load into the calculation. Since effects of emissions have to be assessed on a greater scale, such as on the European air traffic network, the presented approach provides cost functions for CO2 emissions for different aircraft types and load factors. The cost functions were derived by means of regression analyses of BADA based calculated flight profiles with a step size of one second. The calculations are based on real historic traffic scenarios over several days. The derived aircraft specific fuel burn coefficients enable a simple and efficient integration of CO2 estimations depending on the flight distance, load factor and aircraft type. This can be applied to large traffic scenarios to also study different set-ups such as travel restrictions, other disruptions or an alteration in the traffic system as a whole. In order to enable the assessment of further aspects of such changes to the European air traffic system at large and to foster reproducibility and comparability of related studies, we provide further general-purpose cost estimation functions for several important key characteristics. Besides fuel consumption, we develop cost estimations for air navigation fees and maintenance for conventional aircraft. Those functions are also provided for the design concept of a short-range all-electric aircraft. This propeller aircraft features game-changing technologies such as active laminar flow control, active load alleviation and advanced materials and structure concepts. The approaches discussed in this paper will focus on the generic aspects of aircraft related costs, which can be derived from general available data. For the sake of reproducibility, the results will be made publicly available. [ABSTRACT FROM AUTHOR]

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AbstractBackground: In a previous study, we found stress to increase crevicular interleukin-1ß (Il-1ß) secretion induced by supragingival plaque. While in that study, stress and plaque were presented concomitantly, we now wondered whether a consecutive presentation of these 2 factors would still exert stress effects. Method: 39 medical students participated in the study; 18 took part in a major exam while the remaining 21 served as controls. From the day after the last exam, students neglected oral hygiene in 2 antagonistic quadrants for 21 days (experimental gingivitis), while they maintained perfect hygiene at the remaining sites. Crevicular fluid samples were taken at days 0, 5, 8, 15, 18, and 21 of experimental gingivitis. Results: A significant effect of pre-exposure to academic stress on crevicular Il-1ß concentration was found (area under the curve: p=0.042), the effect size, however, being smaller than in our previous study when stress and plaque were presented concomitantly. Conclusions: It is concluded that pre-exposure to stress may persistently alter the immunological effects of microbial challenge to the periodontium. [ABSTRACT FROM AUTHOR]

A local version of the theory of homomorphs and Schunck classes is given. It is shown that for any finite soluble group the pronormal subgroups are precisely the covering subgroups with respect to 'Schunck sets' in this group. As an application simple proofs of some results on pronormal subgroups of finite soluble groups are obtained. Finally a question of Doerk is answered in the negative: any finite soluble group is a subgroup of a minimal non-trivial pronormal subgroup of some finite soluble group. [ABSTRACT FROM AUTHOR]

In connection with the justified demand to analyze the motivation of going in for sports in its full extent and integrity, the authors here present a strategy of analysis that comprises nearly all aspects underlying the object adequate approach to the determination of complex personality traits. The essential task of this strategy is to identify the developmental level of complex personality traits and their relations to other traits under simultaneous consideration of all essential elements that belong to a trait ensemble as theoretically defined representative of the complex trait by means of an adequate ensemble of indicators. The total relation among single motives served to define frequent motive profiles, further the complex relation to physical activity is discussed. On this basis first conclusions are drawn as to how to integrate young people even more into regular sporting activity. The insight into different motivational structures and sport motivations among various social and demographic groups enables the planning and management of sport-related youth leisure activities to offer sports, which in their contents and form meet these very needs. In accordance with the motivational structures, the sports offered will have to be different for single than for married persons, and different for young workers than for members of the intelligentsia, etc.