Fak. 4 Elektrotechnik und Informatik

1822 Items

Recent Submissions
Efficient Tuning-Free l 1-Regression of Nonnegative Compressible Signals

Petersen, Hendrik Bernd ; Bah, Bubacarr ; Jung, Peter (2021-06-07)

In compressed sensing the goal is to recover a signal from as few as possible noisy, linear measurements with the general assumption that the signal has only a few non-zero entries. The recovery can be performed by multiple different decoders, however most of them rely on some tuning. Given an estimate for the noise level a common convex approach to recover the signal is basis pursuit denoising...

An Online Data Visualization Feedback Protocol for Motor Imagery-Based BCI Training

Duan, Xu ; Xie, Songyun ; Xie, Xinzhou ; Obermayer, Klaus ; Cui, Yujie ; Wang, Zhenzhen (2021-06-07)

Brain–computer interface (BCI) has developed rapidly over the past two decades, mainly due to advancements in machine learning. Subjects must learn to modulate their brain activities to ensure a successful BCI. Feedback training is a practical approach to this learning process; however, the commonly used classifier-dependent approaches have inherent limitations such as the need for calibration ...

Risk-aware control, dispatch and coordination in sustainable power systems

Mieth, Robert (2021)

A timely transition towards a sustainable carbon-neutral power sector requires modern power systems to host increasing numbers of renewable energy sources (RES) and other non-traditional distributed energy sources (DER). However, the stochastic nature and limited controllability of these resources undermines the efficiency of current power system and market operations and creates new forms of p...

Temperatures estimation system of electrical machines on wireless sensor networks

Huang, Yi (2021)

This dissertation proposes a model-based software method to develop a temperatures estimation system for an asynchronous machine, which is implemented in wireless sensor networks (WSN). The system can estimate the temperatures of the stator winding, the rotor cage and the stator core. Firstly, a physical model of an asynchronous machine is built and validated in Dymola. The electrical, mechani...

Fix with P6: Verifying Programmable Switches at Runtime

Shukla, Apoorv ; Hudemann, Kevin ; Vági, Zsolt ; Hügerich, Lily ; Smaragdakis, Georgios ; Hecker, Artur ; Schmid, Stefan ; Feldmann, Anja (2021-05)

We design, develop, and evaluate P6, an automated approach to (a) detect, (b) localize, and (c) patch software bugs in P4 programs. Bugs are reported via a violation of pre-specified expected behavior that is captured by P6. P6 is based on machine learning-guided fuzzing that tests P4 switch non-intrusively, i.e., without modifying the P4 program for detecting runtime bugs. This enables an auto...

Implications of the COVID-19 Pandemic on the Internet Traffic

Feldmann, Anja ; Gasser, Oliver ; Lichtblau, Franziska ; Pujol, Enric ; Poese, Ingmar ; Dietzel, Christoph ; Wagner, Daniel ; Wichtlhuber, Matthias ; Tapiador, Juan ; Vallina-Rodriguez, Narseo ; Hohlfeld, Oliver ; Smaragdakis, Georgios (2021-03)

In this paper, we report on a measurement study by researchers from several institutions that collected and analyzed network data to assess the impact of the first wave of COVID-19 (February-June 2020) on the Internet traffic. The datasets from Internet Service Providers, Internet Exchange Points, and academic networks, primarily in Europe, provide a unique view on the changes of Internet traff...

Veränderung des Internetverkehrs während der ersten Welle der COVID-19-Pandemie

Feldmann, Anja ; Gasser, Oliver ; Lichtblau, Franziska ; Pujol, Enric ; Poese, Ingmar ; Dietzel, Christoph ; Wagner, Daniel ; Wichtlhuber, Matthias ; Tapiador, Juan ; Vallina-Rodriguez, Narseo ; Hohlfeld, Oliver ; Smaragdakis, Georgios (2021-04)

Während der COVID-19-Pandemie ist das Internet für die Aufrechterhaltung vieler Gesellschaftsbereiche als Kommunikationsinfrastruktur von essentieller Bedeutung, beispielspeise im Homeschooling oder im Homeoffice. So sehr die Pandemie unser gesellschaftliches Leben verändert, so sehr verändert sie auch den Internetverkehr und es stellen sich aufgrund des sprunghaften Anstieges der Internetnutzu...

User Interaction Templates for the Design of Lifelogging Systems

Hopfgartner, Frank ; Yang, Yang ; Zhou, Lijuan Marissa ; Gurrin, Cathal (2013)

A variety of life-tracking devices are being created to give opportunity to track our daily lives accurately and automatically through the application of sensing technologies. Technology allows us to automatically and passively record life activities in previously unimaginable detail, in a process called lifelogging. Captured materials may include text, photos/video, audio, location, Bluetooth ...

Detecting Violent Content in Hollywood Movies and User-generated Videos

Acar, Esra ; Irrgang, Melanie ; Maniry, Dominique ; Hopfgartner, Frank (2015-01-15)

Detecting violent scenes in videos is an important content understanding functionality, e.g., for providing automated youth protection services. The key issues in designing violence detection algorithms are the choice of discriminative features and learning effective models. We employ low and mid-level audio-visual features and evaluate their discriminative power within the context of the Media...

Gamification of Workplace Activities

Meder, Michael ; Jain, Brijnesh Johannes ; Plumbaum, Till ; Hopfgartner, Frank (2015-01-15)

Gamification—taking game design patterns and principles out of video games to apply them in non-game environments has become a popular idea in the last 4 years. It has also successfully been applied to workplace environments, but it still remains unclear how employees really feel about the introduction of a gamified system. We address this matter by comparing the employees’ subjective perceptio...

Health Assistance for Immigrants

Plumbaum, Till ; Klein-Ellinghaus, Funda ; Reeske, Anna ; Pelz, Kristin ; Hopfgartner, Frank (2015-01-15)

Our personal health should be one of our main concerns, but unfortunately, due to modern lifestyle, far too many people ignore their own well-being. Consequently, methodologies need to be developed that assist us in living a healthier life. In this chapter, we present a health assistance system for immigrants. The system consists of two parts: A health information system that allows users to se...

Multimedia Retrieval and Adaptive Systems

Frank, Hopfgartner (2013-11)

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Berlin Robust Orientation Estimation Assessment Dataset (BROAD)

Laidig, Daniel (2021-06-11)

Data files and example code for the BROAD benchmark for inertial orientation estimation. For more details, see the following publication: D. Laidig, M. Caruso, A. Cereatti, T. Seel. BROAD -- A Benchmark for Robust Inertial Orientation Estimation. Submitted to Data. A copy of this dataset is also available at https://github.com/dlaidig/broad.

Second life assessment of Lithium-ion cells obtained from portable electronics

Salinas, Felipe (2021)

In the last decade, repurposing batteries obtained from electric vehicles as stationary energy storages has gained attention motivated by the life extension of lithium-ion batteries before recycling. This interest is also observed in initiatives which have downscaled this concept for batteries obtained from portable electronics, accounting today for most batteries sent to recycling. Independent...

Scalable and privacy-preserving off-chain computations

Eberhardt, Jacob (2021)

Blockchains are distributed systems that allow mutually distrusting parties to process transactions in a censorship-resistant way while establishing an immutable transaction history without trusting a third party. These properties, however, do not come for free. Unlike other large-scale distributed systems, blockchains do not scale. They suffer from low transaction throughput and high costs res...

A Year in Lockdown: How the Waves of COVID-19 Impact Internet Traffic

Feldmann, Anja ; Gasser, Oliver ; Lichtblau, Franziska ; Pujol, Enric ; Poese, Ingmar ; Dietzel, Christoph ; Wagner, Daniel ; Wichtlhuber, Matthias ; Tapiador, Juan ; Vallina-Rodriguez, Narseo ; Hohlfeld, Oliver ; Smaragdakis, Georgios (2021-06)

In March 2020, the World Health Organization declared the COVID-19 outbreak a global pandemic. As a result, billions of people were either encouraged or forced by their governments to stay home to reduce the spread of the virus. This caused many to turn to the Internet for work, education, social interaction, and entertainment. With the Internet demand rising at an unprecedented rate, the quest...

A view of Internet Traffic Shifts at ISP and IXPs during the COVID-19 Pandemic

Feldmann, Anja ; Gasser, Oliver ; Lichtblau, Franziska ; Pujol, Enric ; Poese, Ingmar ; Dietzel, Christoph ; Wagner, Daniel ; Wichtlhuber, Matthias ; Tapiador, Juan ; Vallina-Rodriguez, Narseo ; Hohlfeld, Oliver ; Smaragdakis, Georgios (2020-11)

Due to the COVID-19 pandemic, many governments imposed lockdowns that forced hundreds of millions of citizens to stay at home. The implementation of confinement measures increased Internet traffic demands of residential users, in particular, for remote working, entertainment, commerce, and education, which, as a result, caused traffic shifts in the Internet core. In this paper, using data from ...

Identifying Sensitive URLs at Web-Scale

Matic, Srdjan ; Iordanou, Costas ; Smaragdakis, Georgios ; Laoutaris, Nikolaos (2020-10-27)

Several data protection laws include special provisions for protecting personal data relating to religion, health, sexual orientation, and other sensitive categories. Having a well-defined list of sensitive categories is sufficient for filing complaints manually, conducting investigations, and prosecuting cases in courts of law. Data protection laws, however, do not define explicitly what type ...

Who's left behind? Measuring Adoption of Application Updates at Scale

Rula, John P. ; Richter, Philipp ; Smaragdakis, Georgios ; Berger, Arthur (2020-10-27)

This work presents a large-scale, longitudinal measurement study on the adoption of application updates, enabling continuous reporting of potentially vulnerable software populations worldwide. Studying the factors impacting software currentness, we investigate and discuss the impact of the platform and its updating strategies on software currentness, device lock-in effects, as well as user beha...

Keep your Communities Clean: Exploring the Routing Message Impact of BGP Communities

Krenc, Thomas ; Beverly, Robert ; Smaragdakis, Georgios (2020-11-23)

BGP communities are widely used to tag prefix aggregates for policy, traffic engineering, and inter-AS signaling. Because individual ASes de ne their own community semantics, many ASes blindly propagate communities they do not recognize. Prior research has shown the potential security vulnerabilities when communities are not filtered. This work sheds light on a second unintended side-effect of ...