Konstanze Kölle

Dr. Konstanze Kölle


Research Focus & Metrics

Academic Career Length

9Years (2018-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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24 May 2021 in Advanced Control for Applications
Verified
Journal Article
Open access
PDF file
IEIrene Eguinoa
Irene Eguinoa
TGTuhfe Göçmen
Tuhfe Göçmen
PGPaula B. Garcia-Rosa
Paula B. Garcia-Rosa
KDKaushik Das
Kaushik Das
VPVlaho Petrović
Vlaho Petrović
MSMichael Smailes
Michael Smailes
Wind farm control (WFC) allows coordinated operation of the wind turbines within a wind power plant (WPP). However, its development has traditionally been split into the distinct disciplines of power plant control and farm flow control. As variable renewable energies, in particular wind energy, increase their penetration into the power system, grid code requirements become stricter for WPPs and electricity markets necessarily evolve. In such a context, crossfertilization between the two categories of WFC, targeting an integrated approach where applicable, becomes a priority. An initial overview on how to further align wind farm flow control (WFFC) to grid and electricity markets participation is provided, including an analysis of capabilities and prospects. In addition, greater detail is given about an open‐access dataset serving as market showcases for value demonstration of price‐driven operation of WPPs by means of WFFC.

2 April 2019 in IEEE Journal of Biomedical and Health Informatics
Verified
Journal Article
Closed access
KKKonstanze Kölle
Konstanze Kölle
TBTorben Biester
Torben Biester
SCSverre Christian Christiansen
Sverre Christian Christiansen
AFAnders Lyngvi Fougner
Anders Lyngvi Fougner
OSOyvind Stavdahl
Oyvind Stavdahl
Accurate continuous glucose monitoring (CGM) is essential for fully automated glucose control in diabetes mellitus type 1. State-of-the-art glucose control systems automatically regulate the basal insulin infusion. Users still need to manually announce meals to dose the prandial insulin boluses. An automated meal detection could release the user and improve the glucose regulation. In this study, patterns in the postprandial CGM data are exploited for meal detection. Binary classifiers are trained to recognize the postprandial pattern in horizons of the estimated glucose rate of appearance and in CGM data. The appearance rate is determined by moving horizon estimation (MHE) based on a simple model. Linear discriminant analysis (LDA) is used for classification. The proposed method is compared to methods that detect meals when thresholds are violated. Diabetes care data from twelve free-living pediatric patients was downloaded during regular screening. Experts identified meals and their start by retrospective evaluation. The classification was tested by cross-validation. Compared to the threshold-based methods, LDA showed higher sensitivity to meals with a low rate of false alarms. Classifying horizons outperformed the other methods also with respect to time of detection. The onset of meals can be detected by pattern recognition based on estimated model states and consecutive CGM measurements. No individual tuning is necessary. This makes the method easily adopted in the clinical practice.

11 September 2019 in IEEE Journal of Translational Engineering in Health and Medicine
Verified
Journal Article
Open access
KKKonstanze Kölle
Konstanze Kölle
AFAnders Lyngvi Fougner
Anders Lyngvi Fougner
REReinold Ellingsen
Reinold Ellingsen
SCSven Magnus Carlsen
Sven Magnus Carlsen
OSOyvind Stavdahl
Oyvind Stavdahl
Background In classical approaches for an artificial pancreas, continuous glucose monitoring (CGM) is the only measured variable used for insulin dosing and additional control functions. The CGM values are subject to time delays and slow dynamics between blood and the sensing location. These time lags compromise the controller’s performance in maintaining (near to) normal glucose levels. Meal information could enhance the control outcome. However, meal announcement by the user is not reliable, and it takes 30 min to 40 min from meal onset until a meal is detected by methods based on CGM. In this pilot study, the use of bowel sounds for meal detection was investigated. In particular, we focused on whether bowel sounds change qualitatively during or shortly after meal ingestion. Methods After fasting for at least 4 h, 11 healthy volunteers ingested a lunch meal at their usual time. Abdominal sound was recorded by a condenser microphone that was attached to the right upper quadrant of the abdomen by medical tape. Features that describe the power distribution over the frequency spectrum were extracted and used for classification by support vector machines. These classifiers were trained in a leave-one-out cross-validation scheme. Results Meals could be detected on average after less than 10 min with the best parameter choice. Conclusion This shows that abdominal sound monitoring could provide an early meal detection. Further studies should investigate this possibility on a larger population in more general settings.

3 November 2022 in Wind Energy Science
Verified
Journal Article
Open access
PDF file
KKKonstanze Kölle
Konstanze Kölle
TGTuhfe Göçmen
Tuhfe Göçmen
IEIrene Eguinoa
Irene Eguinoa
LRLeonardo Andrés Alcayaga Román
Leonardo Andrés Alcayaga Román
MAMaria Aparicio-Sanchez
Maria Aparicio-Sanchez
ISIshaan Sood
Ishaan Sood
The EU and UK have made ambitious commitments under the net-zero plans to decarbonise their economies by 2050. For this, offshore wind will play a major role, significantly contributing to a paradigm shift in the power generation and greater volatility of electricity prices. The operating strategy of wind farms should therefore move from power maximisation to profit maximisation which includes income from providing power system services and the reduction of maintenance costs. Wind farm flow control (WFFC) is a key enabler for this shift through mitigation of wake effects in the design and operation phases. The results of the FarmConners market showcases presented here are the first attempt to economically assess WFFC strategies with respect to electricity market prices. Here, we present a conceptual simulation study starting from individual turbine control and extend it to layouts with 10 and 32 turbines operated with WFFC based on the results of five participants. Each participant belonged to a different research group with their respective simulation environments, flow models and WFFC strategies. Via a comparative analysis of relative WFFC benefits estimated per participant, the implications of wind farm size, the applied control strategy and the overall model fidelity are discussed in zero-subsidy scenarios. For all the participants, it is seen that the income gain can differ significantly from the power gain depending on the electricity price under the same inflow, and a favourable control strategy for dominant wind directions can pay off even for low electricity prices. However, a strong correlation between income and power gain is also observed for the analysed high-electricity-price scenarios, underlining the need for additional modelling capabilities to carry out a more comprehensive value optimisation including lower prices and system requirements driven cases.

20 March 2019 in BioMedical Engineering OnLine
Verified
Journal Article
Open access
PDF file
KKKonstanze Kölle
Konstanze Kölle
MAMuhammad Faisal Aftab
Muhammad Faisal Aftab
LALeif Erik Andersson
Leif Erik Andersson
AFAnders Lyngvi Fougner
Anders Lyngvi Fougner
ØSØyvind Stavdahl
Øyvind Stavdahl
The analysis of abdominal sounds can help to diagnose gastro-intestinal diseases. Sounds originating from the stomach and the intestine, the so-called bowel sounds, occur in various forms. They are described as loose successions or clusters of rather sudden bursts. Realistic recordings of abdominal sounds are contaminated with noise and artifacts from which the bowel sounds must be differentiated. The proposed intrinsic mode function-fractal dimension (IMF-FD) filtering utilizes the property of the multivariate empirical mode decomposition (MEMD) to behave as a series of band pass filters. The MEMD decomposes the abdominal signal into its different frequency components. The resulting intrinsic mode functions (IMFs) are modulated in amplitude and frequency where transient sonic events occur. Based on the complexity of the IMFs, measured by their fractal dimension (FD) in sliding windows, the information-carrying IMFs are selected. The filtered signal is formed as the superposition of all selected IMFs. The IMF-FD filter not only enhances the non-linear components of the original signal but also segments them from the rest. Another important aspect of this work is that typical artifacts that occur in the same frequency range as bowel sounds can be subsequently eliminated by heuristic rules. The method is tested on a realistic, contaminated data set with promising performance: close to 100% of the manually labeled bowel sounds are identified.

30 October 2018 in Health and Technology
Verified
Journal Article
Closed access
PDF file
KKKonstanze Kölle
Konstanze Kölle
AFAnders Lyngvi Fougner
Anders Lyngvi Fougner
MLMary Ann Lundteigen
Mary Ann Lundteigen
SCSven Magnus Carlsen
Sven Magnus Carlsen
REReinold Ellingsen
Reinold Ellingsen
ØSØyvind Stavdahl
Øyvind Stavdahl