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Item type:Publication, Access status: without files , Smart grid co-simulation with MOSAIK and HLA: a comparison studyEvaluating new technological developments for energy systems is becoming more and more complex. The overall application environment is a continuously growing and interconnected cyber-physical system so that analytical assessment is practically impossible to realize. Consequently, new solutions must be evaluated in simulation studies. Due to the interdisciplinarity of the simulation scenarios, various heterogeneous tools must be connected. This approach is known as co-simulation. During the last years, different approaches have been developed or adapted for applications in energy systems. In this paper, two co-simulation approaches are compared that follow generic, versatile concepts. The tool mosaik, which has been explicitly developed for the purpose of co-simulation in complex energy systems, is compared to the High Level Architecture (HLA), which possesses a domain-independent scope but is often employed in the energy domain. The comparison is twofold, considering the tools’ conceptual architectures as well as results from the simulation of representative test cases. It suggests that mosaik may be the better choice for entry-level, prototypical co-simulation while HLA is more suited for complex and extensive studies.Publicationtype: Journal Article40 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Understanding price functions to control domestic electric water heaters for demand response: A bilevel approach to adapt power consumption to availabilty(2018-02-01); ; ; A well-known mechanism for demand response is sending price signals to customers a day ahead. Customers then postpone or advance their usage of electricity to minimize cost. Setting up price functions that adapt the customers’ load to availability is a big challenge. This paper investigates the feasibility of finding day-ahead price functions to induce a desired load profile of domestic electric water heaters (DEWHs) minimizing their electricity cost for demand response. Bilevel optimization is applied for a single DEWH using a simplified linear model and full knowledge. This leads to a solvable bilevel problem and allows understanding optimality of price functions and resulting heating profiles. It is shown that with the resulting price functions the DEWH may select many significantly different heating profiles leading to the same cost. Thus the price does not uniquely induce the desired heating profile. The acquired knowledge forms the basis for a procedure to create price functions for controlling the load profile of many DEWHs.Publicationtype: Journal Article78 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Impacts of domestic electric water heater parameters on demand response: a simulative analysis of physical and control parameter impactsThis paper analyzes the impact of the high dimensional parameter space of domestic electric water heaters (DEWH) for demand response (DR). To quantify the consumer comfort a novel metric is introduced considering a stochastic distribution of different water draw events. Incorporating three control algorithms from literature, it is shown that all considered parameters of a DEWH except the heat conductivity have a significant impact on consumer satisfaction. The effect on DR is mainly influenced by the temperature range and the planning horizon, but also by the heat conductivity and the volume. In contrast, the rated power of the heating element and the nominal temperature have no significant impact on the effect on DR. The impacts are analyzed by varying these parameters in a simulation of 1000 DEWHs considering three different controllers: a common thermostat, an exchange price dependent nominal temperature changing mechanism and an energy scheduling algorithm proposed by Du and Lu.Publicationtype: Journal Article80 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Energy-aware analysis of electrically long high speed I/O linksThis paper presents a novel approach for an energy-aware analysis of electrically long high speed I/O links. ABCD-parameters are used to analyze the passive link model, which takes into account termination impedances at transmitter and receiver as well as the network parameters of the interconnect. Voltage transfer function and input impedance of the link model are used to carry out a combined evaluation of frequency dependent signal transmission and power consumption of the link. The combined analysis allows to carry out an optimization of the energy efficiency under the given constraints. It is applied to a realistic high speed backplane link, which is modeled using measured interconnect network parameters. Simulated interconnect network parameters are used to study the impact of link improvements on signal transmission and power consumption.Publicationtype: Journal Article43 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Model-based segmentation of pediatric and adult joints for orthopedic measurements in digital radiographs of the lower limbs(Springer, 2010-11-11); ; ; ; The growth of human bones forms a major problem when automatically segmenting orthopedic radiographs. Any template-based segmentation methods fails to fully capture these non-linear developments. However to extract orthopedic measurements or the bone age for patients of arbitrary age it is mandatory to have a segmentation scheme that deals with growth related changes. In this paper we propose a robust method based on Active Shape Models (ASMs) that on the one hand is invariant against the patient's age and on the other hand generalizes well over the large inter-patient variability. Our method achieves an accuracy of 0.48 mm for adult patients and 0.64 mm for children on a large test set of 180 images, with the patient's age covering a high range from less than one month to 93 years.Publicationtype: Conference Paper33