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We present a digital phase-locked loop (DPLL) operating from 2.8 to 3.8 GHz with an on-chip 40-MHz reference crystal oscillator. The DPLL makes use of a class-D digitally controlled oscillator and a digital-to-time converter with a single-bit (bang-bang) phase detector. The DPLL displays an excellent behavior in terms of in-band fractional spurs, which are consistently below -65 dBc across the tun
Reference Attribute Grammars (RAGs) is a declarative executable formalism used for constructing compilers and related tools. Existing implementations support concurrent evaluation only with global evaluation locks. This may lead to long latencies in interactive tools, where interactive and background threads query attributes concurrently.We present lock-free algorithms for concurrent attribute eva
Adverse environmental and social conditions early in life have a strong impact on health. They are major risk factors for mental diseases in adulthood and, in some cases, their effects can be transmitted across generations. The consequences of detrimental stress conditions on brain metabolism across generations are not well known. Using high-field (14.1 T) magnetic resonance spectroscopy, we inves
Brain glutamine synthetase (GS) is an integral part of the glutamate-glutamine cycle and occurs in the glial compartment. In vivo Magnetic Resonance Spectroscopy (MRS) allows noninvasive measurements of the concentrations and synthesis rates of metabolites. (15)N MRS is an alternative approach to (13)C MRS. Incorporation of labeled (15)N from ammonia in cerebral glutamine allows to measure several
The increased impact from fluctuating energy sources like wind and photovoltaics significantly affects the operational regime of conventional power plants. In the near future, even former base load power plants such as the large-scale lignite plants in Germany will need to start and shut down to balance the electricity system. As frequent starts were not in the focus of optimisation in the past, a
A physical network node controls allocation and/or deallocation of resources of an interconnected hardware infrastructure. The physical network node determines a number of requests currently queued at a first service node of a plurality of serially-connected service nodes at a current time. The plurality of serially-connected service nodes supports a packet flow using resources of the interconnect
Proportional-integral-derivative (PID) controllers are very common in the process industry. In a regular factory there may be hundreds or thousands of them in use. Each of these controllers needs to be tuned, and even though the PID controller is simple, tuning the controllers still requires several hours of work and adequate knowledge in order to achieve a desired performance. Because of that, ma
Goal understanding and communication of requirements are vital for ensuring that large and complex project organizations collaborate efficiently. We have used a design science approach to explore and address the problem of communication for large IT projects. We designed a method for avoiding communication gaps by eliciting information regarding stakeholders and information flows. The MAPS (Mappin
A multi-variable PI (proportional integrating) controller is proved to be optimal for an important class of control problems where performance is specified in terms of frequency weighted H-infinity norms. The problem class includes networked systems with a subsystem in each node and control action along each edge. For such systems, the optimal PI controller is decentralized in the sense that contr
This paper develops a novel framework for power system stability analysis, that allows for the decentralised design of inverter based controllers. The method requires that each individual inverter satisfies a standard H∞ design requirement. Critically each requirement depends only on the dynamics of the components and inverters at each individual bus, and the aggregate susceptance of the transmiss
Modeling of robot motion as dynamical movement primitives (DMPs) has becomean important framework within robot learning and control. The ability of DMPs to adapt online with respect to the surroundings, e.g., to moving targets, has been used and developed by several researchers. In this work, a method for handling perturbations during execution of DMPs on robots was developed. Two-degree-of-freedo
We show how to minimize the energy required to build up the electromagnetic field in radio-frequency cavities, which will allow power savings for pulsed particle accelerators. By formulating an optimal control problem for a first-order system we obtain a solution on state-feedback form. We numerically compare the optimal solution to previous approaches.
This paper presents an algorithm for Model Predictive Control of SISO systems. Based on a quadratic objective in addition to (hard) input constraints it features soft upper as well as lower constraints on the output and an input rate-of-change penalty term. It keeps the deterministic and stochastic model parts separate. The controller is designed based on the deterministic model, while the Kalman
The fast-increasing demand and relatively slow growth of infrastructure capacity are providing a strong motivation for research in real-time urban traffic controls that make the best use of novel sensing in order to increase efficiency and resilience of the transportation system. In our contribution, we focus on a class of dynamic feedback traffic signal control policies that are based on a genera
Relay autotuning has proven very successful for single-input single-output systems. This paper proposes an identification method for relay autotuning of systems with two inputs and two outputs (TITO systems). The combination of asymmetric relay feedback and output error identification admits short tuning time, without the need for limit cycle convergence. The method is successfully demonstrated on
Control and scheduling co-design becomes an issue when several controller tasks share the same execution platform and disrupt the ideal sampling and actuation patterns. In co-design the objective is to optimize the combined performance of all the controllers on the platform, subject to schedulability constraints. In the paper four LQG-based co-design methods are reviewed and evaluated: delay-aware
The paper presents conditions for the stability of a dynamical network described by a directed graph, whose nodes represent dynamical systems characterised by the same transfer function F(s) and whose edges account for the interactions between pairs of nodes. In turn, these interactions depend via a transference G(s) on the outputs of the subsystems associated with the connected nodes. The stabili
An adaptive uplink detection scheme for a Massive MIMO (MaMi) base station serving up to 16 users is presented. Considering user distribution in a cell, selective matched filtering (MF) is proposed for non-interference limited users and a Cholesky decomposition (CD) based zero-forcing (ZF) detector is implemented for the remaining users. Channel conditions such as coherence bandwidth are exploited
In wavefield signal apparition, acquisition with periodic variations in source activation parameters shifts all or part of a signal cone out to, e.g., the Nyquist wavenumber, enabling perfect separation of simultaneous-source (sim-source) data in a diamond-shaped region below a certain temporal frequency. Cyclic convolution in the spatial frequency domain can be exploited to separate data with kno
In digital control systems, the state is sampled at given sampling instants and the input is kept constant between two consecutive instants. With the optimal sampling problem, we mean the selection of sampling instants and control inputs, such that a given function of the state and input is minimized. In this paper, we formulate the optimal sampling problem and we derive a necessary condition of t
