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There is a growing interest to estimate the inherent uncertainty of photovoltaic (PV) power forecasts with probability forecasting methods to enable a robust operational planning of energy systems. The aim of this paper is to present a detailed comparison of probabilistic extensions for time series models regarding their practical applicability, as these are still widely used in the field. For this purpose, five probabilistic forecasting methods are analyzed for intraday PV power forecast with respect to their reliability, sharpness and computational complexity. There may be limited data sets available for the initial commissioning in industrial applications. Hence, the analyses are performed using sliding windows of respectively one, three, five and seven weeks of training data. The investigations are carried out with three roof-mounted PV systems from Germany and Austria. An adaptive ARX model is applied as the underlying point forecast, which uses decomposed past PV power measurements and an external weather forecast for the next day as input features. Results suggest that with the methods presented in this paper, already seven days of training data are sufficient to produce significant improvements of up to 45 % in forecasting quality compared to the reference case. Additionally, the quantile regression approaches outperform the bootstrapping approaches slightly in terms of forecast quality and significantly in terms of required computation time.

Regulated Electricity Price Components (REPCs) such as fees, taxes and levies dominate the cost structure for every consumed, stored, or even generated kWh of electricity in Germany and other European countries. This decreases financial incentives for flexible consumption, storage or generation which will be needed to handle increasing volatility in generation and demand.In this paper, we propose a linear optimization-based market matching mechanism for Local Energy Markets (LEMs) which considers REPCs. With this approach, the REPCs can be split and allocated to substations, feeders, and participants thereby incentivizing trades within close spatial proximity.We compare different schemes for spatially distributed REPCs for a demonstration scenario with 120 LEM participants with electric vehicles, battery storage and solar PV systems. Compared to a business as usual scenario, local self-sufficiency can be increased by about 14 percentage points. Additionally, peak loads during midday and evening can be decreased by 13-58 %.

We introduce blueprint separable convolutions (BSConv) as highly efficient building blocks for CNNs. They are motivated by quantitative analyses of kernel properties from trained models, which show the dominance of correlations along the depth axis. Based on our findings, we formulate a theoretical foundation from which we derive efficient implementations using only standard layers. Moreover, our approach provides a thorough theoretical derivation, interpretation, and justification for the application of depthwise separable convolutions (DSCs) in general, which have become the basis of many modern network architectures. Ultimately, we reveal that DSC-based architectures such as MobileNets implicitly rely on cross-kernel correlations, while our BSConv formulation is based on intra-kernel correlations and thus allows for a more efficient separation of regular convolutions. Extensive experiments on large-scale and fine-grained classification datasets show that BSConvs clearly and consistently improve MobileNets and other DSC-based architectures without introducing any further complexity. For fine-grained datasets, we achieve an improvement of up to 13.7 percentage points. In addition, if used as drop-in replacement for standard architectures such as ResNets, BSConv variants also outperform their vanilla counterparts by up to 9.5 percentage points on ImageNet. Code and models are available under https://github.com/zeiss-microscopy/BSConv., Published at CVPR 2020. Code and models are available under https://github.com/zeiss-microscopy/BSConv

Providing students with the necessary mathematical skills is a growing challenge in German engineering degree courses. This is due to manifold mostly pre-university reasons, for example, inadequate or heterogeneous secondary education in Germany. Preparatory courses, a common remedy offered by many universities, often turn out to lack the expected effect. However, implying an early, mandatory test that scans the basic mathematical skills defined as entrance standard, showed positive results, as it detects the individual knowledge gaps of first-year students and motivates them to take action. For this purpose, we coupled the test with detailed, individual feedback and a cluster of affiliated support offers – preparatory to the test as well as attendant to the first year. Being mandatory, the test already pushes more students in our preparatory math courses. Whereas its detailed, individual feedback enables students to choose among the subsequent support offers and to cope with remaining gaps. The support offers range from transition workshops, co-learning tutorials, an online exercise platform, video tutorials up to conventional worksheets and consultation hours. This setup of mandatory test, early and detailed feedback and versatile supporting offers, tackling the missing skills, significantly increased the success in the basic mathematics and mathematics dependent modules of our engineering bachelor courses. In the process, this setup generates several additional, statistical outcomes, like a rating of the different German pre-university school systems, which helps to further work on measures dealing with the decreasing skills of beginners.

The article proposes to determine, discuss and qualify how the Framework Scrum Higher Education - based on the original Framework Scrum Version 2017 - supports teachers and students to recognize the difficulties and challenges related to the intended learning outcome and the missing motivation of students' learning process. The study aims to answer several research questions, e.g. what is the effect of a value-based framework and the intervention by a Scrum Master on students’ agile and critical performance in teamwork? The team performance was diagnosed by applying a set of tools to measure the capacity for teamwork. The evaluation confirms that agile and collaborative adaption of Scrum for Higher Education improves the self-learning process, self-motivation and self-emotion for the learner. Especially the event Sprint-Retrospective with the tailor-made framework for the Definition of Flow plays a key role and the Scrum Master gets a chance for solution-focused coaching in a convenient phase of reflection. The paper shows empirical results of a quantitative survey, which analyses quality criteria of teamwork during the sprints of the Scrum Framework. As an agile method of learning, students figured out their own learning and team working obstacles by using the solution-focused coaching.

Task-based Programming Learning (TBPL) is an approach which is based on ideas of Task-based Language Learning in second language acquisition. It can use output-prompting and input-providing tasks. This paper describes the theoretical background and methodical aspects of the input-providing TBPL variant and its implementation in higher education courses. The approach was implemented and evaluated in five different programming courses from both students (N=165) and lecturers (N=4). It became clear that the TBPL-approach has several positive aspects and that it can serve as a valuable instrument for learning and teaching programming in higher education.

Contemporary mobile devices have become universal and versatile tools that increasingly are used in sensitive application scenarios. They inevitably carry confidential information such as passwords, encryption keys, mission-critical company data, or location information in combat areas. In order to meet sophisticated security requirements, recent technology focuses on policy-oriented approaches that allow for the definition and enforcement of rigorous and precise rules for protecting confidential information. State-of-the-art development of security policies is a critical process, because of the involved quality assurance measures, it is quite heavy-weighted and tends to antagonize the distinguished virtues of mobile devices for lightweight, spontaneous communication and cooperation. This paper presents an approach to support secure, mobile device based cooperation in temporary, sporadically and spontaneously fashioned cliques within open communication infrastructures. The approach is based upon light-weight security domains protected by security policies that are dynamically and automatically composed during group formation. Due to the volatile nature of such groups simplicity, adaptability, efficiency and compatibility with today's security policy implementation techniques have been a major design goal.

Exciton-polariton lasers are operated in the strong light matter coupling regime. They promise low threshold operation since population inversion is not inherently necessary. Hence they are of great interest for next generation coherent light sources.

The issue of this paper is a fast and robust online calibration method for a multi laser tracking system (MLTS). The MLTS is able to track the movement of a retro-reflector that can be mounted on an arbitrary target. After introducing the MLTS and its functionality, the algorithm based on trilateration is depicted. The key issues applying the trilateration are varying parameters, which are dependent on the initial position of the target. In order to solve this problem a fast and robust calibration algorithm is proposed. The applied optimization algorithm, a Gauss-Newton approach, is explained, implemented and tested on a real time control system. After describing the calibration process the MLTS is explored by reference to measurements. The results are discussed and affecting factors are stated.

Wavelength-division multiplexing filters are photonic key components for the distribution of multiple optical channels. Microring and racetrack resonators in add/drop configuration can be employed to perform the signal routing. In this work, low-loss hydrogenated amorphous silicon (a-Si:H) was employed as waveguide core material as it is transparent in the near infrared and can be fabricated at low costs and with low temperatures (

The presented work concerns a new identification algorithm for the elasto-plastic friction model. The algorithm is based on the physical effects that are described by this model. As a result there are separate experiments for the breakaway, the elastic and the plastic range containing the exact performance of the respective range. The breakaway range signifies the boundary between the elastic and the plastic range. Its linear spring damper behavior determines the elastic range whereas the Stribeck curve describes the plastic range. The exact parameters are separately calculated through specific experiments referring to their physical equivalent. The paper describes these experiments in detail. In contrast to an overall parameter identification based on an optimization to fit one measurement this paper focuses on the identification of the parameters with the best physical analogy to real friction behavior.

The a-Si:H deposition process is systematically investigated in intrawafer and wafer-to-wafer experiments. Photonic ring resonators were studied within-chip and chip-to-chip, showing ±1.2nm resonance peak variations and deviations of 0.25% (intrachip) and 0.9%(interchip) for group index and FSR.

We report about the fabrication and optical characterization of high Q hydrogenated amorphous silicon microdisk resonators in telecommunication C-band. High resonance peaks of >30dB were achieved. Intrinsic Q-factors of 0.9×106 were measured with >10dB extinction for qTM-modes.

In this paper, we present a model-based tracking control of a positioning stage using laser trackers as contactless position feedback sensor. The laser trackers follow the stage in the complete working range and the position of the stage is determined with the laser triangulation method. Based on this very precise position information a trajectory tracking controller with friction compensation was developed. The dynamical behavior of the stage without friction is modeled as a differential equation second order and the model parameters are identified by experiment. Based on this model a PD controller is designed using pole placement method. In the feedforward path of the trajectory tracking controller a Basic Maxwell-Slip friction model is utilized for friction cancellation. In order to identify the parameters of the friction model the Dynamic NonLinear Regression with direct application of eXcitation (DNLRX) identification algorithm is used. It is shown by experiment that the proposed control approach reduces the tracking error significantly.

Since security has become an essential asset in numerous application areas, the integration of security policies has become a major issue in the design of security architectures, and many commodity operating systems have been furnished with abstractions to support policy protection and enforcement.

A cost-efficient way to achieve high-accuracy motion control is the utilization of complex control algorithms. Hence advanced motion control constitutes a class of real-time applications, for which the technical feasibility strongly depends on the achievable execution performance on the embedded processing platform. The presented modular controller structure defines a set of advanced control algorithms able minimize the tracking error, even for friction affected kinematics. Transferring the controller design to an implementation-oriented modelling level focuses on minimizing the processing latency in order to realize the required high sample rate. The utilization or even the custom development of a parallel platform becomes inevitable, which is why it is necessary to integrate both, control and embedded platform development processes. The presented process includes controller design, platform mapping and architecture optimization to address the challenge of tailoring an application-specific modular embedded processing platform already on the modelling level before interfacing state-of-the-art tool chains.

The presented work concerns the modeling and experimental verification of the highly nonlinear behavior in positioning on the nanometer scale. The main goal of this work is to identify and extend a simple dynamic friction model, which allows a model-based estimation of the friction force including the system inertia only based on a displacement input. Experiments in the pre-sliding and sliding friction regimes are conducted on a high precision positioning stage. A hybrid parameter estimation algorithm is used offline to fit the model parameters based on the experimental data. Extensive experiments show, that the system behavior of the experimental setup is highly position dependent and hence the inverse system model is not valid over the whole operating range of the positioning stage. To solve this problem the parameters of the friction model are adjusted online to ensure precise friction estimation over the positioning range of 200 mm. Finally, an adaptive model is utilized as a model-based friction compensator in a trajectory tracking control scheme. With this adaptive control approach the tracking error is reduced significantly.

An optic switch of SOI-nanowires with a very low power consumption of less than 1 mW is presented. The nanowires are placed on freestanding electrostatically deflectable SiO 2 -membranes to tune them thermo-optically and elasto-optically.

This work concerns a non-model-based friction compensation scheme for dynamic position control on nanometer scale. The main goal of this work is to build up and implement a simple dynamic friction observer which allows an estimation of the friction force in combination with the system inertia against displacement. Experiments in the pre-sliding and sliding friction regimes are conducted on an experimental setup. After a short review of friction compensation, the experimental setup is explained in detail. Next, the observer is modeled mathematically and the used control scheme is presented. Finally, the friction observer is utilized as a non-model-based friction estimator combined with a classical feedback controller to compensate the nonlinear friction force and reduce tracking errors significantly. It is shown that the proposed controlling approach is able to realize a fast and ultra precise positioning over long distances.

The elasto-optic and the thermo-optic effect in silicon nanowires is demonstrated using Mach-Zehnder interferometers. The nanowires are placed on undercut SiO2 membranes which can be deflected electrostatically.

In this paper a simple contact lithography with i-line or DUV is used for the production of photonic wires, which are additionally smoothed and shrunk by thermal oxidation.

A rib-like spot-size converter was fabricated with a KOH etched shadow mask. The improvement in coupling and an expansion of the spot-size were evaluated with simulations and confirmed by transmission loss measurements.

Electrons accelerated in laser plasma generated gamma-bremsstrahlung. The gamma-radiation was used for radiography with a time-resolved imaging system. We determined the modulation transfer function of the imaging system and have produced position and time-resolved gamma-images.

We report the first production of quasi-monoenergetic proton beams using laser plasmas. Supported by scalability studies, this puts laser plasma acceleration clearly in the scope of medical application.

We demonstrate for the first time photo-proton nuclear reactions in various nuclei induced by a high-intensity, high repetition rate table-top laser and measure ratios of photo-proton/photo-neutron cross-sections

We demonstrate the precise spatial and temporal overlap of two counter-propagating, focused laser pulses at intensities above the relativistic threshold. In a first experiment a single-shot autocorrelation was carried out. Further applications are discussed

Electron and proton beams were investigated using a compact laser with intensities up to 2times1019 W/cm2 irradiating thin targets. For the direction of the electron beam theory and experiment disagree