Elektrotechnik und Informatik (ETI)
Refine
Publication Type
- Conference Proceeding (21) (remove)
Language
- German (21) (remove)
Keywords
- Analysis (1)
- Cyber Security (1)
- Deep Learning (1)
- Development and implementation (1)
- End of charge (1)
- GNSS (1)
- Highly Sensitive (1)
- Hochintegrierte Mikro- und Nanosysteme (1)
- M-health, machine learning, website (1)
- Modellfabrik, Industrie 4.0, Cyber-Physical Systems, Durchgängige Digitalisierung, Autonomer mobiler Roboter, Lehre (1)
This paper deals with the issue of automating the
process of machine learning and analyzing bio-datasets. For this
a user-friendly website has been developed for the interaction
with the researchers. On this website it is possible to upload
datasets and to share them, if desired, with other scientists. The
uploaded data can also be analyzed by various methods and
functions. The signals inside these datasets can also be visualized.
Furthermore several algorithms have been implemented to create
machine learning models with the uploaded data. Based on these
generated models new data can be classified or calculated. For all
these applications the simplest possible handling was
implemented to make the website available to all interested
researchers.
Metal air batteries provide a high energy density as the ca-thodic reaction uses the surrounding air. Different metals can be usedbut zinc is very promising due to its disposability and nontoxic behav-ior. State estimation is quite complicated as the voltage characteristicof the battery is rather flat. Especially estimating the state of chargeis important as a secondary electrolysis process during overcharging canlead to an unsafe state. Another technique for state estimation is theelectrochemical impedance spectroscopy. Therefore, this paper describesthe process of setup and measuring a time series of impedance spectraat known states of charge. Then these spectra are used to derive anequivalent circuit. Finally the development of the circuit’s parameter areanalyzed to extract most important parameters.
The main task of battery management systems is to keep the working area of the battery in a safe state. Estimation of the state of charge and the state of health is therefore essential. The traditional way uses the voltage level of a battery to determine those values. Modern metal air batteries provide a flat voltage characteristic which necessitates new approaches. One promising technique is the electrochemical impedance spectroscopy, which measures the AC resistance for a set of different frequencies. Previous approaches match the measured impedances with a nonlinear equivalent circuit, which needs a lot of time to solve a nonlinear least-squares problem. This paper combines the electrochemical impedance spectroscopy with neural networks to speed up the state estimation using the example of zinc air batteries. Moreover, these networks are trained with different subsets of the spectra as input data in order to determine the required number of frequencies.
OpenPGP and S/MIME are the two major standards to en-crypt and digitally sign emails. Digital signatures are sup-posed to guarantee authenticity and integrity of messages. Inthis work we show practical forgery attacks against variousimplementations of OpenPGP and S/MIME email signatureverification in five attack classes: (1) We analyze edge casesin S/MIME’s container format. (2) We exploit in-band sig-naling in the GnuPG API, the most widely used OpenPGPimplementation. (3) We apply MIME wrapping attacks thatabuse the email clients’ handling of partially signed mes-sages. (4) We analyze weaknesses in the binding of signedmessages to the sender identity. (5) We systematically testemail clients for UI redressing attacks.Our attacks allow the spoofing of digital signatures for ar-bitrary messages in 14 out of 20 tested OpenPGP-capableemail clients and 15 out of 22 email clients supportingS/MIME signatures. While the attacks do not target the un-derlying cryptographic primitives of digital signatures, theyraise concerns about the actual security of OpenPGP andS/MIME email applications. Finally, we propose mitigationstrategies to counter these attacks.
We show practical attacks against OpenPGP and S/MIMEencryption and digital signatures in the context of email. Instead of tar-geting the underlying cryptographic primitives, our attacks abuse legiti-mate features of the MIME standard and HTML, as supported by emailclients, to deceive the user regarding the actual message content. Wedemonstrate how the attacker can unknowingly abuse the user as a de-cryption oracle by replying to an unsuspicious looking email. Using thistechnique, the plaintext of hundreds of encrypted emails can be leakedat once. Furthermore, we show how users could be tricked into signingarbitrary text by replying to emails containing CSS conditional rules.An evaluation shows that "out of" OpenPGP-capable email clients,as well as "out of" clients supporting S/MIME, are vulnerable to atleast one attack. We provide different countermeasures and discuss theiradvantages and disadvantages.
When developing new battery technologies, fundamental research means assembling new batteries by hand since a production line is not worthwhile for building and testing individual cells. This causes high production tolerances to occur because manual manufacturing is not as precise as machine-made. When putting these prototypes into operation, problems can arise due to the varying parameters. One of the most important exercise is finding a criterion of a full battery. This can be challenging when parameters like the capacity or the end of charge voltage are not precisely known due to the tolerances. Furthermore, new battery types do not necessarily rely on the same stopping criteria. For example zinc-air secondary batteries do not offer an end of charging voltage. Its charging current is not going to decrease when the battery is full and the charging voltage is held at a fixed value. But instead of de-oxidising zinc oxide, hydrogen is produced. In the majority of cases overcharging should be avoided as it harms the battery. Another even more dangerous consequence is the possibility of an explosion. Especially lithium based batteries are known for their need of compatible ambient and charging parameters. This paper proposes a new criterion for detecting the end of charge that is based on the rate of change of electrochemical impedance spectra of the examined batteries. Device parameter fluctuations influence every measurement. Therefore, using the rate of change offers the possibility to not depend on these fluctuations.