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317 results on '"Schwefel, Hans-Peter"'

1. A stochastic approach to estimate distribution grid state with confidence regions

Author

Olsen, Rasmus L., Hassani, Sina, Pedersen, Troels, Rasmussen, Jakob Gulddahl, and Schwefel, Hans-Peter

Subjects
Statistics - Applications
Abstract

Widely available measurement equipment in electrical distribution grids, such as power-quality measurement devices, substation meters, or customer smart meters do not provide phasor measurements due to the lack of high resolution time synchronisation. Instead such measurement devices allow to obtain magnitudes of voltages and currents and the local phase angle between those. In addition, these measurements are subject to measurement errors of up to few percent of the measurand. In order to utilize such measurements for grid monitoring, this paper presents and assesses a stochastic grid calculation approach that allows to derive confidence regions for the resulting current and voltage phasors. Two different metering models are introduced: a PMU model, which is used to validate theoretical properties of the estimator, and an Electric Meter model for which a Gaussian approximation is introduced. The estimator results are compared for the two meter models and case study results for a real Danish distribution grid are presented.

Published
2024

2. Increased Renewable Hosting Capacity of a Real Low-Voltage Grid Based on Continuous Measurements – Results from an Actual PV Connection Request

Author

Schäler, Christine, Strasser, Klaus, Damböck, Robert, Schwefel, Hans-Peter, Filipe, Joaquim, Editorial Board Member, Ghosh, Ashish, Editorial Board Member, Prates, Raquel Oliveira, Editorial Board Member, Zhou, Lizhu, Editorial Board Member, Adler, Rasmus, editor, Bennaceur, Amel, editor, Burton, Simon, editor, Di Salle, Amleto, editor, Nostro, Nicola, editor, Olsen, Rasmus Løvenstein, editor, Saidi, Selma, editor, Schleiss, Philipp, editor, Schneider, Daniel, editor, and Schwefel, Hans-Peter, editor

Published
2021
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3. Power Loss Reduction in Low-Voltage Distribution Grids via Coordinated Reactive Power Management of PV Inverters

Author

Gui, Yonghao, Schwefel, Hans-Peter, Bendtsen, Jan Dimon, Stoustrup, Jakob, Filipe, Joaquim, Editorial Board Member, Ghosh, Ashish, Editorial Board Member, Prates, Raquel Oliveira, Editorial Board Member, Zhou, Lizhu, Editorial Board Member, Adler, Rasmus, editor, Bennaceur, Amel, editor, Burton, Simon, editor, Di Salle, Amleto, editor, Nostro, Nicola, editor, Olsen, Rasmus Løvenstein, editor, Saidi, Selma, editor, Schleiss, Philipp, editor, Schneider, Daniel, editor, and Schwefel, Hans-Peter, editor

Published
2021
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4. Fast Abstracts and Student Forum Proceedings - EDCC 2016 - 12th European Dependable Computing Conference

Author

Tredan, Gilles and Schwefel, Hans Peter

Subjects
Computer Science - Distributed, Parallel, and Cluster Computing
Abstract

Fast Abstracts are short presentations of work in progress or opinion pieces and aim to serve as a rapid and flexible mechanism to (i) Report on current work that may or may not be complete; (ii) Introduce new ideas to the community; (iii) State positions on controversial issues or open problems. On the other hand, the goal of the Student Forum is to encourage students to attend EDCC and present their work, exchange ideas with researchers and practitioners, and get early feedback on their research efforts., Comment: 12th European Dependable Computing Conference, Gothenburg, Sweden, September 5-9, 2016

Published
2016

5. Location-Quality-aware Policy Optimisation for Relay Selection in Mobile Networks

Author

Nielsen, Jimmy J., Olsen, Rasmus L., Madsen, Tatiana K., Uguen, Bernard, and Schwefel, Hans-Peter

Subjects
Computer Science - Networking and Internet Architecture
Abstract

Relaying can improve the coverage and performance of wireless access networks. In presence of a localisation system at the mobile nodes, the use of such location estimates for relay node selection can be advantageous as such information can be collected by access points in linear effort with respect to number of mobile nodes (while the number of links grows quadratically). However, the localisation error and the chosen update rate of location information in conjunction with the mobility model affect the performance of such location-based relay schemes; these parameters also need to be taken into account in the design of optimal policies. This paper develops a Markov model that can capture the joint impact of localisation errors and inaccuracies of location information due to forwarding delays and mobility; the Markov model is used to develop algorithms to determine optimal location-based relay policies that take the aforementioned factors into account. The model is subsequently used to analyse the impact of deployment parameter choices on the performance of location-based relaying in WLAN scenarios with free-space propagation conditions and in an measurement-based indoor office scenario., Comment: Accepted for publication in ACM/Springer Wireless Networks

Published
2015

11. Investigating Wind Farm Control Over Different Communication Network Technologies

Author

Madsen, Jacob Theilgaard, Findrik, Mislav, Drenjanac, Domagoj, Schwefel, Hans-Peter, Hutchison, David, Series editor, Kanade, Takeo, Series editor, Kittler, Josef, Series editor, Kleinberg, Jon M., Series editor, Mattern, Friedemann, Series editor, Mitchell, John C., Series editor, Naor, Moni, Series editor, Pandu Rangan, C., Series editor, Steffen, Bernhard, Series editor, Terzopoulos, Demetri, Series editor, Tygar, Doug, Series editor, Weikum, Gerhard, Series editor, Gottwalt, Sebastian, editor, König, Lukas, editor, and Schmeck, Hartmut, editor

Published
2015
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12. Addressing the Influence of Hidden State on Wireless Network Optimizations Using Performance Maps

Author

Højgaard-Hansen, Kim, Madsen, Tatiana K., Schwefel, Hans-Peter, Hutchison, David, Series editor, Kanade, Takeo, Series editor, Kittler, Josef, Series editor, Kleinberg, Jon M., Series editor, Mattern, Friedemann, Series editor, Mitchell, John C., Series editor, Naor, Moni, Series editor, Pandu Rangan, C., Series editor, Steffen, Bernhard, Series editor, Terzopoulos, Demetri, Series editor, Tygar, Doug, Series editor, Weikum, Gerhard, Series editor, Balandin, Sergey, editor, Andreev, Sergey, editor, and Koucheryavy, Yevgeni, editor

Published
2015
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13. Information-Quality Based LV-Grid-Monitoring Framework and Its Application to Power-Quality Control

Author

Findrik, Mislav, le Fevre Kristensen, Thomas, Hinterhofer, Thomas, Olsen, Rasmus L., Schwefel, Hans-Peter, Hutchison, David, Series editor, Kanade, Takeo, Series editor, Kittler, Josef, Series editor, Kleinberg, Jon M., Series editor, Mattern, Friedemann, Series editor, Mitchell, John C., Series editor, Naor, Moni, Series editor, Pandu Rangan, C., Series editor, Steffen, Bernhard, Series editor, Terzopoulos, Demetri, Series editor, Tygar, Doug, Series editor, Weikum, Gerhard, Series editor, Papavassiliou, Symeon, editor, and Ruehrup, Stefan, editor

Published
2015
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14. Network-Independent Clock Offset Estimation Using Correlated Sensor Data

Author

Taha, Adham, Thorsager, Mathias Drekjær, Krøyer, Sune, Madsen, Tatiana Kozlova, and Schwefel, Hans-Peter Christian

Subjects
SDG 7 - Affordable and Clean Energy
Abstract

In many distributed sensing use-cases, sensor nodes need to allocate a time-stamp to sensed data. When combining data from different sensors across different sensors, it is important to have synchronized timestamps. When using wireless sensor networks (WSNs) without dedicated hardware such as GPS clock, keeping the sensors synchronised via synchronization protocols will increase communication overhead and the resulting clock accuracy will depend on the latency and jitter of the end-to-end wireless communication paths. In order to become independent of the wireless transmission medium, this paper investigates an alternative approach where the sensed signals with spatial correlation are utilized to achieve clock synchronization. A number of methods are proposed that use maximization of the correlation coefficient to estimate the time shift between two sensing time series. Furthermore, it is shown that a jump detection can be applied as a feature extraction step. The performance evaluation results, obtained using a dedicated testbed, show that the proposed solutions are capable of estimating the offset between two sensor nodes, without imposing additional communication strain and without being affected by the network conditions of the WSN.

Published
2023

16. Model-Based Decision Framework for Autonomous Application Migration

Author

Nickelsen, Anders, Olsen, Rasmus L., Schwefel, Hans-Peter, Hutchison, David, Series editor, Kanade, Takeo, Series editor, Kittler, Josef, Series editor, Kleinberg, Jon M., Series editor, Mattern, Friedemann, Series editor, Mitchell, John C., Series editor, Naor, Moni, Series editor, Nierstrasz, Oscar, Series editor, Pandu Rangan, C., Series editor, Steffen, Bernhard, Series editor, Sudan, Madhu, Series editor, Terzopoulos, Demetri, Series editor, Tygar, Doug, Series editor, Vardi, Moshe Y., Series editor, Weikum, Gerhard, Series editor, Al-Begain, Khalid, editor, Balsamo, Simonetta, editor, Fiems, Dieter, editor, and Marin, Andrea, editor

Published
2011
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17. Erdschlusslokalisierung basierend auf transienten Spannungsmessungen am Umspannwerk:Erfahrungen aus drei realen Mittelspannungsnetzen

Author

Wörmann, Julian, Schäler, Christine, Duchon, Markus, and Schwefel, Hans-Peter Christian

Subjects
Verdensmål 7 - Bæredygtig energi
Abstract

Ein neues datenbasiertes Verfahren zur Lokalisierung von Erdschlussfehlern unter Verwendung transienter Spannungs-messungen am Umspannwerk wird vorgestellt und in realen Mittelspannungsnetzen dreier regionaler Verteilnetzbetreiber validiert. Der Ansatz lokalisiert sowohl stehende Erdschlüsse als auch Erdschlusswischer und stellt nur minimale Anfor-derungen an den Netzbetreiber, ist also sehr einfach in fast jede Systemumgebung des Stromverteilnetzbetreibers integrierbar. Die Funktionalität des Ansatzes konnte am Beispiel von acht realen Erdschlussmessungen in drei verschiedenen Mittelspannungsnetzen gezeigt werden. Sieben der Erdschlussereignisse wurden erfolgreich lokalisiert; dazu wurde in dem stark verzweigten ländlichen Mischnetz zusätzlich nur ein einzelner Erdschlussrichtungsanzeiger benötigt, um Mehrdeutigkeiten auszuschließen. Diese messdatenbasierte Lokalisierung erfolgt innerhalb weniger Minuten ohne zusätzliche Schaltvorgänge.

Published
2022

19. Modeling Movable Components for Disruption Tolerant Mobile Service Execution

Author

Gabner, Rene, Hummel, Karin Anna, Schwefel, Hans-Peter, Akan, Ozgur, editor, Bellavista, Paolo, editor, Cao, Jiannong, editor, Dressler, Falko, editor, Ferrari, Domenico, editor, Gerla, Mario, editor, Kobayashi, Hisashi, editor, Palazzo, Sergio, editor, Sahni, Sartaj, editor, Shen, Xuemin, editor, Stan, Mircea, editor, Xiaohua, Jia, editor, Zomaya, Albert, editor, Coulson, Geoffrey, editor, Avresky, Dimiter R., editor, Diaz, Michel, editor, Bode, Arndt, editor, Ciciani, Bruno, editor, and Dekel, Eliezer, editor

Published
2010
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20. Service Migration Protocol for NFC Links

Author

Nickelsen, Anders, Martin, Miquel, Schwefel, Hans-Peter, Hutchison, David, editor, Kanade, Takeo, editor, Kittler, Josef, editor, Kleinberg, Jon M., editor, Mattern, Friedemann, editor, Mitchell, John C., editor, Naor, Moni, editor, Nierstrasz, Oscar, editor, Pandu Rangan, C., editor, Steffen, Bernhard, editor, Sudan, Madhu, editor, Terzopoulos, Demetri, editor, Tygar, Doug, editor, Vardi, Moshe Y., editor, Weikum, Gerhard, editor, Aagesen, Finn Arve, editor, and Knapskog, Svein Johan, editor

Published
2010
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21. Dependability Evaluation of a Replication Service for Mobile Applications in Dynamic Ad-Hoc Networks

Author

Matthiesen, Erling V., Hamouda, Ossama, Kaâniche, Mohamed, Schwefel, Hans-Peter, Hutchison, David, editor, Kanade, Takeo, editor, Kittler, Josef, editor, Kleinberg, Jon M., editor, Mattern, Friedemann, editor, Mitchell, John C., editor, Naor, Moni, editor, Nierstrasz, Oscar, editor, Pandu Rangan, C., editor, Steffen, Bernhard, editor, Sudan, Madhu, editor, Terzopoulos, Demetri, editor, Tygar, Doug, editor, Vardi, Moshe Y., editor, Weikum, Gerhard, editor, Nanya, Takashi, editor, Maruyama, Fumihiro, editor, Pataricza, András, editor, and Malek, Miroslaw, editor

Published
2008
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22. A Comparative Study of Forward Error Correction and Frame Accumulation for VoIP over Congested Networks

Author

Præstholm, Steffen, Schwefel, Hans-Peter, Andersen, Søren Vang, Hutchison, David, editor, Kanade, Takeo, editor, Kittler, Josef, editor, Kleinberg, Jon M., editor, Mattern, Friedemann, editor, Mitchell, John C., editor, Naor, Moni, editor, Nierstrasz, Oscar, editor, Pandu Rangan, C., editor, Steffen, Bernhard, editor, Sudan, Madhu, editor, Terzopoulos, Demetri, editor, Tygar, Doug, editor, Vardi, Moshe Y., editor, Weikum, Gerhard, editor, Mason, Lorne, editor, Drwiega, Tadeusz, editor, and Yan, James, editor

Published
2007
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23. Client-Centric Performance Analysis of a High-Availability Cluster

Author

Grønbæk, Jesper, Frejek, Hans-Peter, Renier, Thibault, Schwefel, Hans-Peter, Hutchison, David, editor, Kanade, Takeo, editor, Kittler, Josef, editor, Kleinberg, Jon M., editor, Mattern, Friedemann, editor, Mitchell, John C., editor, Naor, Moni, editor, Nierstrasz, Oscar, editor, Rangan, C. Pandu, editor, Steffen, Bernhard, editor, Sudan, Madhu, editor, Terzopoulos, Demetri, editor, Tygar, Doug, editor, Vardi, Moshe Y., editor, Weikum, Gerhard, editor, Malek, Miroslaw, editor, Reitenspieß, Manfred, editor, and van Moorsel, Aad, editor

Published
2007
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24. Inconsistency Evaluation in a Replicated IP-Based Call Control System

Author

Renier, Thibault, Matthiesen, Erling, Schwefel, Hans-Peter, Prasad, Ramjee, Hutchison, David, editor, Kanade, Takeo, editor, Kittler, Josef, editor, Kleinberg, Jon M., editor, Mattern, Friedemann, editor, Mitchell, John C., editor, Naor, Moni, editor, Nierstrasz, Oscar, editor, Pandu Rangan, C., editor, Steffen, Bernhard, editor, Sudan, Madhu, editor, Terzopoulos, Demetri, editor, Tygar, Dough, editor, Vardi, Moshe Y., editor, Weikum, Gerhard, editor, Penkler, Dave, editor, Reitenspiess, Manfred, editor, and Tam, Francis, editor

Published
2006
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27. Distributed Redundancy or Cluster Solution? An Experimental Evaluation of Two Approaches for Dependable Mobile Internet Services

Author

Renier, Thibault, Schwefel, Hans-Peter, Bozinovski, Marjan, Larsen, Kim, Prasad, Ramjee, Seidl, Robert, Hutchison, David, editor, Kanade, Takeo, editor, Kittler, Josef, editor, Kleinberg, Jon M., editor, Mattern, Friedemann, editor, Mitchell, John C., editor, Naor, Moni, editor, Nierstrasz, Oscar, editor, Pandu Rangan, C., editor, Steffen, Bernhard, editor, Sudan, Madhu, editor, Terzopoulos, Demetri, editor, Tygar, Dough, editor, Vardi, Moshe Y., editor, Weikum, Gerhard, editor, Malek, Miroslaw, editor, Reitenspieß, Manfred, editor, and Kaiser, Jörg, editor

Published
2005
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28. Increased Renewable Hosting Capacity of a Real Low-Voltage Grid Based on Continuous Measurements:Results from an Actual PV Connection Request

Author

Schaeler, Christine, Strasser, Klaus, Damböck, Robert, Schwefel, Hans-Peter Christian, Adler, Rasmus, Bennaceur, Amel, Burton, Simon, Di Salle, Amleto, Nostro, Nicola, Olsen, Rasmus Løvenstein, Saidi, Selma, Schleiss, Philipp, Schneider, Daniel, and Schwefel, Hans-Peter

Subjects
Grid measurements, digital twin, electricity distribution grids, Hosting capacity, Low-voltage grid, SDG 7 - Affordable and Clean Energy, planning, Computer Science::Distributed, Parallel, and Cluster Computing
Abstract

The distributed generation and new load patterns caused by the energy transition put strong requirements on the distribution grids. The traditional worst-case planning approaches in the low-voltage grid will lead to excessive grid extensions. In this paper, through a digital twin of the low-voltage grid, the true status of the physical grid is used to detect grid bottlenecks and therefore allows to match grid investments to actual needs in the distribution grid. This paper presents preliminary results from a real case study for the novel planning approach which lead to an accurate picture of grid hosting capacity, which is a major step forward from previously used worst case assumptions.

Published
2021

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