TY - JOUR
AB - Brainwaves have demonstrated to be unique enough across individuals to be useful as biometrics. They also provide promising advantages over traditional means of authentication, such as resistance to external observability, revocability, and intrinsic liveness detection. However, most of the research so far has been conducted with expensive, bulky, medical-grade helmets, which offer limited applicability for everyday usage. With the aim to bring brainwave authentication and its benefits closer to real world deployment, we investigate brain biometrics with consumer devices. We conduct a comprehensive measurement experiment and user study that compare five authentication tasks on a user sample up to 10 times larger than those from previous studies, introducing three novel techniques based on cognitive semantic processing. Furthermore, we apply our analysis on high-quality open brainwave data obtained with a medical-grade headset, to assess the differences. We investigate both the performance, security, and usability of the different options and use this evidence to elicit design and research recommendations. Our results show that it is possible to achieve Equal Error Rates as low as 7.2% (a reduction between 68–72% with respect to existing approaches) based on brain responses to images with current inexpensive technology. We show that the common practice of testing authentication systems only with known attacker data is unrealistic and may lead to overly optimistic evaluations. With regard to adoption, users call for simpler devices, faster authentication, and better privacy.
AU - Arias-Cabarcos, Patricia
AU - Fallahi, Matin
AU - Habrich, Thilo
AU - Schulze, Karen
AU - Becker, Christian
AU - Strufe, Thorsten
ID - 48063
IS - 3
JF - ACM Transactions on Privacy and Security
KW - Safety
KW - Risk
KW - Reliability and Quality
KW - General Computer Science
SN - 2471-2566
TI - Performance and Usability Evaluation of Brainwave Authentication Techniques with Consumer Devices
VL - 26
ER -
TY - JOUR
AU - Winkel, Fabian
AU - Deuse-Kleinsteuber, Johannes
AU - Böcker, Joachim
ID - 48058
JF - IEEE Transactions on Reliability
KW - Electrical and Electronic Engineering
KW - Safety
KW - Risk
KW - Reliability and Quality
SN - 0018-9529
TI - Run-to-Failure Relay Dataset for Predictive Maintenance Research With Machine Learning
ER -
TY - JOUR
AB - Encrypting data before sending it to the cloud ensures data confidentiality but requires the cloud to compute on encrypted data. Trusted execution environments, such as Intel SGX enclaves, promise to provide a secure environment in which data can be decrypted and then processed. However, vulnerabilities in the executed program give attackers ample opportunities to execute arbitrary code inside the enclave. This code can modify the dataflow of the program and leak secrets via SGX side channels. Fully homomorphic encryption would be an alternative to compute on encrypted data without data leaks. However, due to its high computational complexity, its applicability to general-purpose computing remains limited. Researchers have made several proposals for transforming programs to perform encrypted computations on less powerful encryption schemes. Yet current approaches do not support programs making control-flow decisions based on encrypted data.
We introduce the concept of
dataflow authentication
(DFAuth) to enable such programs. DFAuth prevents an adversary from arbitrarily deviating from the dataflow of a program. Our technique hence offers protections against the side-channel attacks described previously. We implemented two flavors of DFAuth, a Java bytecode-to-bytecode compiler, and an SGX enclave running a small and program-independent trusted code base. We applied DFAuth to a neural network performing machine learning on sensitive medical data and a smart charging scheduler for electric vehicles. Our transformation yields a neural network with encrypted weights, which can be evaluated on encrypted inputs in
\( 12.55 \,\mathrm{m}\mathrm{s} \)
. Our protected scheduler is capable of updating the encrypted charging plan in approximately 1.06 seconds.
AU - Fischer, Andreas
AU - Fuhry, Benny
AU - Kußmaul, Jörn
AU - Janneck, Jonas
AU - Kerschbaum, Florian
AU - Bodden, Eric
ID - 31844
IS - 3
JF - ACM Transactions on Privacy and Security
KW - Safety
KW - Risk
KW - Reliability and Quality
KW - General Computer Science
SN - 2471-2566
TI - Computation on Encrypted Data Using Dataflow Authentication
VL - 25
ER -
TY - THES
AB - Reliability-adaptive systems allow an adaptation of system behavior based on current system reliability. They can extend their lifetime at the cost of lowered performance or vice versa. This can be used to adapt failure behavior according to a maintenance plan, thus increasing availability while using up system capability fully. To facilitate setup, a control algorithm independent of a degradation model is desired. A closed loop control technique for reliability based on a health index, a measure for system degradation, is introduced. It uses self-optimization as means to implement behavior adaptation. This is based on selecting the priorities of objectives that the system pursues. Possible working points are computed beforehand using model-based multiobjective optimization techniques. The controller selects the priorities of objectives and this way balances reliability and performance. As exemplary application, an automatically actuated single plate dry clutch is introduced. The entire reliability control is setup and lifetime experiments are conducted. Results show that the variance of time to failure is reduced greatly, making the failure behavior more predictable. At the same time, the desired usable lifetime can be extended at the cost of system performance to allow for changed maintenance intervals. Together, these possibilities allow for greater system usage and better planning of maintenance.
AU - Meyer, Tobias
ID - 9994
KW - dependability
KW - reliability
KW - behavior adaptation
KW - self-optimization
KW - multiobjective optimization
KW - optimal control
KW - automotive drivetrain
KW - clutch system
KW - reliability-adaptive system
TI - Optimization-based reliability control of mechatronic systems
ER -
TY - CONF
AB - The integrated modeling of behavior and reliability in system development delivers a model-based approach for reliability investigation by taking into account the dynamic system behavior as well as the system architecture at different phases of the development process. This approach features an automated synthesis of a reliability model out of a behavior model enabling for the closed loop modeling of degradation of the system and its (dynamic) behavior. The approach is integrated into the development process following Systems Engineering. It is based on standard models used in model-based development methodologies i.e. SysML or Matlab/Simulink. In addition to the theoretical description of the necessary steps the procedure is validated by an application example at two stages of the development process.
AU - Hentze, Julian
AU - Kaul, Thorben
AU - Grässler, Iris
AU - Sextro, Walter
ID - 9974
KW - Design for X (DfX)
KW - Product modelling / models
KW - Robust design
KW - Systems Engineering (SE)
KW - Reliability
T2 - ICED17, 21st International conference on enginieering design
TI - Integrated modeling og behavior and reliability in system development
ER -
TY - JOUR
AB - State-of-the-art mechatronic systems offer inherent intelligence that enables them to autonomously adapt their behavior to current environmental conditions and to their own system state. This autonomous behavior adaptation is made possible by software in combination with complex sensor and actuator systems and by sophisticated information processing, all of which make these systems increasingly complex. This increasing complexity makes the design process a challenging task and brings new complex possibilities for operation and maintenance. However, with the risk of increased system complexity also comes the chance to adapt system behavior based on current reliability, which in turn increases reliability. The development of such an adaption strategy requires appropriate methods to evaluate reliability based on currently selected system behavior. A common approach to implement such adaptivity is to base system behavior on different working points that are obtained using multiobjective optimization. During operation, selection among these allows a changed operating strategy. To allow for multiobjective optimization, an accurate system model including system reliability is required. This model is repeatedly evaluated by the optimization algorithm. At present, modeling of system reliability and synchronization of the models of behavior and reliability is a laborious manual task and thus very error-prone. Since system behavior is crucial for system reliability, an integrated model is introduced that integrates system behavior and system reliability. The proposed approach is used to formulate reliability-related objective functions for a clutch test rig that are used to compute feasible working points using multiobjective optimization.
AU - Kaul, Thorben
AU - Meyer, Tobias
AU - Sextro, Walter
ID - 9976
JF - SAGE Journals
KW - Integrated model
KW - reliability
KW - system behavior
KW - Bayesian network
KW - multiobjective optimization
TI - Formulation of reliability-related objective functions for design of intelligent mechatronic systems
VL - Vol. 231(4)
ER -
TY - CONF
AB - Intelligent mechatronic systems other the possibility to adapt system behavior to current dependability. This can be used to assure reliability by controlling system behavior to reach a pre-defined lifetime. By using such closed loop control, the margin of error of useful lifetime of an individual system is lowered. It is also possible to change the pre-defined lifetime during operation, by adapting system behavior to derate component usage. When planning maintenance actions, the remaining useful lifetime of each individual system has to be taken into account. Usually, stochastic properties of a fleet of systems are analyzed to create maintenance plans. Among these, the main factor is the probability of an individual system to last until maintenance. If condition-based maintenance is used, this is updated for each individual system using available information about its current state. By lowering the margin of error of useful lifetime, which directly corresponds to the time until maintenance, extended maintenance periods are made possible. Also using reliability-adaptive operation, a reversal of degradation driven maintenance planning is possible where a maintenance plan is setup not only according to system properties, but mainly to requirements imposed by maintenance personnel or infrastructure. Each system then adapts its behavior accordingly and fails according to the maintenance plan, making better use of maintenance personnel and system capabilities at the same time. In this contribution, the potential of maintenance plan driven system behavior adaptation is shown. A model including adaptation process and maintenance actions is simulated over full system lifetime to assess the advantages gained.
AU - Meyer, Tobias
AU - Kaul, Thorben
AU - Sextro, Walter
ID - 9949
KW - Adaptive systems
KW - Reliability analysis
KW - Availability
KW - Adaptive control
KW - Maintenance
KW - Self-optimizing systems
KW - Self-optimizing control
KW - Stochastic Petri-nets
T2 - Proceedings of the 9th IFAC Symposium on Fault Detection, Supervision and Safety for Technical Processes
TI - Advantages of reliability-adaptive system operation for maintenance planning
ER -
TY - CONF
AB - In order to increase mechanical strength, heat dissipation and ampacity and to decrease failure through fatigue fracture, wedge copper wire bonding is being introduced as a standard interconnection method for mass production. To achieve the same process stability when using copper wire instead of aluminum wire a profound understanding of the bonding process is needed. Due to the higher hardness of copper compared to aluminum wire it is more difficult to approach the surfaces of wire and substrate to a level where van der Waals forces are able to arise between atoms. Also, enough friction energy referred to the total contact area has to be generated to activate the surfaces. Therefore, a friction model is used to simulate the joining process. This model calculates the resulting energy of partial areas in the contact surface and provides information about the adhesion process of each area. The focus here is on the arising of micro joints in the contact area depending on the location in the contact and time. To validate the model, different touchdown forces are used to vary the initial contact areas of wire and substrate. Additionally, a piezoelectric tri-axial force sensor is built up to identify the known phases of pre-deforming, cleaning, adhering and diffusing for the real bonding process to map with the model. Test substrates as DBC and copper plate are used to show the different formations of a wedge bond connection due to hardness and reaction propensity. The experiments were done by using 500 $\mu$m copper wire and a standard V-groove tool.
AU - Althoff, Simon
AU - Neuhaus, Jan
AU - Hemsel, Tobias
AU - Sextro, Walter
ID - 9868
KW - adhesion
KW - circuit reliability
KW - deformation
KW - diffusion
KW - fatigue cracks
KW - friction
KW - interconnections
KW - lead bonding
KW - van der Waals forces
KW - Cu
KW - adhering process
KW - adhesion process
KW - ampacity improvement
KW - bond quality improvement
KW - cleaning process
KW - diffusing process
KW - fatigue fracture failure
KW - friction energy
KW - friction model
KW - heat dissipation
KW - mechanical strength
KW - piezoelectric triaxial force sensor
KW - predeforming process
KW - size 500 mum
KW - total contact area
KW - van der Waals forces
KW - wedge copper wire bonding
KW - Bonding
KW - Copper
KW - Finite element analysis
KW - Force
KW - Friction
KW - Substrates
KW - Wires
T2 - Electronic Components and Technology Conference (ECTC), 2014 IEEE 64th
TI - Improving the bond quality of copper wire bonds using a friction model approach
ER -
TY - JOUR
AU - Hemsel, Tobias
AU - Bornmann, Peter
AU - Morita, Takeshi
AU - Sondermann-Wölke, Christoph
AU - Sextro, Walter
ID - 9874
JF - Archive of Applied Mechanics
KW - Reliability
KW - Ultrasonic power transducers
KW - FMEA
SN - 0939-1533
TI - Reliability analysis of ultrasonic power transducers
ER -
TY - CONF
AB - So-called reliability adaptive systems are able to adapt their system behavior based on the current reliability of the system. This allows them to react to changed operating conditions or faults within the system that change the degradation behavior. To implement such reliability adaptation, self-optimization can be used. A self-optimizing system pursues objectives, of which the priorities can be changed at runtime, in turn changing the system behavior. When including system reliability as an objective of the system, it becomes possible to change the system based on the current reliability as well. This capability can be used to control the reliability of the system throughout its operation period in order to achieve a pre-defined or user-selectable system lifetime. This way, optimal planning of maintenance intervals is possible while also using the system capabilities to their full extent. Our proposed control system makes it possible to react to changed degradation behavior by selecting objectives of the self-optimizing system and in turn changing the operating parameters in a closed loop. A two-stage controller is designed which is used to select the currently required priorities of the objectives in order to fulfill the desired usable lifetime. Investigations using a model of an automotive clutch system serve to demonstrate the feasibility of our controller. It is shown that the desired lifetime can be achieved reliably.
AU - Meyer , Tobias
AU - Sextro, Walter
ID - 9884
KW - self-optimization reliability adaptive
T2 - Proceedings of the Second European Conference of the Prognostics and Health Management Society 2014
TI - Closed-loop Control System for the Reliability of Intelligent Mechatronic Systems
VL - 5
ER -
TY - JOUR
AU - Vidor, F.F.
AU - Wirth, G.I.
AU - Hilleringmann, Ulrich
ID - 39483
IS - 12
JF - Microelectronics Reliability
KW - Electrical and Electronic Engineering
KW - Surfaces
KW - Coatings and Films
KW - Safety
KW - Risk
KW - Reliability and Quality
KW - Condensed Matter Physics
KW - Atomic and Molecular Physics
KW - and Optics
KW - Electronic
KW - Optical and Magnetic Materials
SN - 0026-2714
TI - Low temperature fabrication of a ZnO nanoparticle thin-film transistor suitable for flexible electronics
VL - 54
ER -
TY - CONF
AU - Anwer, Jahanzeb
AU - Meisner, Sebastian
AU - Platzner, Marco
ID - 10620
KW - fault tolerant computing
KW - field programmable gate arrays
KW - logic design
KW - reliability
KW - BYU-LANL tool
KW - DRM tool flow
KW - FPGA based hardware designs
KW - avionic application
KW - device technologies
KW - dynamic reliability management
KW - fault-tolerant operation
KW - hardware designs
KW - reconfiguring reliability levels
KW - space applications
KW - Field programmable gate arrays
KW - Hardware
KW - Redundancy
KW - Reliability engineering
KW - Runtime
KW - Tunneling magnetoresistance
T2 - Reconfigurable Computing and FPGAs (ReConFig), 2013 International Conference on
TI - Dynamic reliability management: Reconfiguring reliability-levels of hardware designs at runtime
ER -
TY - CONF
AB - To optimize the ultrasound irradiation for cavitation based ultrasound applications like sonochemistry or ultrasound cleaning, the correlation between cavitation intensity and the resulting effect on the process is of interest. Furthermore, changing conditions like temperature and pressure result in varying acoustic properties of the liquid. That might necessitate an adaption of the ultrasound irradiation. To detect such changes during operation, process monitoring is desired. Labor intensive processes, that might be carried out for several hours, also require process monitoring to increase their reliability by detection of changes or malfunctions during operation. In some applications cavitation detection and monitoring can be achieved by the application of sensors in the sound field. Though the application of sensors is possible, this necessitates modifications on the system and the sensor might disturb the sound field. In other applications harsh, process conditions prohibit the application of sensors in the sound field. Therefore alternative techniques for cavitation detection and monitoring are desired. The applicability of an external microphone and a self-sensing ultrasound transducer for cavitation detection were experimentally investigated. Both methods were found to be suitable and easily applicable.
AU - Bornmann, Peter
AU - Hemsel, Tobias
AU - Sextro, Walter
AU - Maeda, Takafumi
AU - Morita, Takeshi
ID - 9783
KW - cavitation
KW - chemical reactors
KW - microphones
KW - process monitoring
KW - reliability
KW - ultrasonic applications
KW - ultrasonic waves
KW - acoustic properties
KW - cavitation based ultrasound applications
KW - cavitation intensity
KW - change detection reliability
KW - external microphone
KW - malfunction detection reliability
KW - nonperturbing cavitation detection
KW - nonperturbing cavitation monitoring
KW - process monitoring
KW - self-sensing ultrasound transducer
KW - sonochemical reactors
KW - sonochemistry
KW - ultrasound cleaning
KW - ultrasound irradiation
KW - Acoustics
KW - Liquids
KW - Monitoring
KW - Sensors
KW - Sonar equipment
KW - Transducers
KW - Ultrasonic imaging
SN - 1948-5719
T2 - Ultrasonics Symposium (IUS), 2012 IEEE International
TI - Non-perturbing cavitation detection / monitoring in sonochemical reactors
ER -
TY - CONF
AB - Recent advances in information processing enable new kinds of technical systems, called self-optimizing systems. These systems are able to adapt their objectives and their behavior according to the current situation and influences autonomously. This behavior adaptation is non-deterministic and hence self-optimization is a risk to the system, e.g. if the result of the self-optimization process does not match the suddenly changed situation. In contrary, self-optimization could be used to increase the dependability by pursuing objectives like reliability and availability. In our preceding publications we introduced the so called multi-level dependability concept to cope with this new kind of systems (cf. [6]). This concept comprises the monitoring of the system behavior, the classification of the current situation, and the selection of the appropriate measure, if reliability limits are exceeded. In this paper we present for the first time experimental results. The dependability concept is implemented in the self-optimizing active guidance system of a railway vehicle. The test drives illustrate clearly that the proposed concept is able to cope with, e.g., sensor failures, and is able to increase the reliability and availability of the active guidance module.
AU - Sondermann-Wölke, Christoph
AU - Geisler, Jens
AU - Sextro, Walter
ID - 9763
KW - availability
KW - dependability concept
KW - multilevel dependability concept
KW - railway vehicle
KW - reliability
KW - self optimizing active guidance system
KW - self optimizing railway guidance system
KW - situation classification
KW - system behavior monitoring
KW - optimal control
KW - railways
KW - reliability theory
KW - self-adjusting systems
SN - 0149-144X
T2 - Reliability and Maintainability Symposium (RAMS), 2010 Proceedings - Annual
TI - Increasing the reliability of a self-optimizing railway guidance system
ER -
TY - CONF
AB - Self-optimizing mechatronic systems are a new class of technical systems. On the one hand, new challenges regarding dependability arise from their additional complexity and adaptivity. On the other hand, their abilities enable new concepts and methods to improve the dependability of mechatronic systems. This paper introduces a multi-level dependability concept for self-optimizing mechatronic systems and shows how planning can be used to improve the availability and reliability of systems in the operating stages.
AU - Klöpper, Benjamin
AU - Sondermann-Wölke, Christoph
AU - Romaus, Christoph
AU - Vöcking, Henner
ID - 9736
KW - multilevel dependability concept
KW - probabilistic planning
KW - self-optimizing mechatronic systems
KW - systems reliability
KW - mechatronics
KW - planning (artificial intelligence)
KW - self-adjusting systems
T2 - Computational Intelligence in Control and Automation, 2009. CICA 2009. IEEE Symposium on
TI - Probabilistic planning integrated in a multi-level dependability concept for mechatronic systems
ER -
TY - CONF
AB - EN: Although the use of new actuator technologies is quite enthusiastic, the realization of innovative systems based on these principles fails because of doubts in dependability. Until now, new working principles for actuators have not been systematically investigated in the means of dependability. Therefore we developed a proceeding for a dependability-oriented evaluation of technologies. This is shown in the case of shape memory alloy actuators.
DE: Die Realisierung von Systemen mittels innovativer Aktortechnologien scheitert oftmals an der Skepsis gegenüber der Verlässlichkeit (Vertrauen in die zuverlässige und sichere Funktionalität der Technologie). Diese liegt darin begründet, dass neue Aktortechnologien bzw. die Integration von innovativen physikalischen Wirkprinzipen innerhalb neuer Aktorkonzepte bisher noch nicht systematisch im Kontext der Verlässlichkeit untersucht werden. Daher haben wir ein Vorgehen zur verlässlichkeitsorientierten Technologiebewertung entwickelt. Neben der detaillierten Darstellung des Vorgehensmodells wird es exemplarisch anhand von Formgedächtnislegierungen zur Entwicklung innovativer Antriebslösungen angewendet.
AU - Müller, Thomas
AU - Schiedeck, Florian
AU - Hemsel, Tobias
ID - 9570
KW - EN: Dependability
KW - Reliability
KW - Evaluation of Technology
KW - Actuators
KW - Shape Memory Alloys DE: Verl{\
T2 - 2. Tagung des DVM -- Arbeitskreis Zuverlässigkeit mechatronischer und adaptronischer Systeme: Absicherung der Systemzuverlässigkeit, Koblenz
TI - Verlässlichkeitorientierte Technologiebewertung innovativer Aktortechnologien am Beispiel von Formgedächtnislegierungen
ER -