@incollection{MonkmanBoeseErmertetal., author = {Monkman, Gareth J. and B{\"o}se, Holger and Ermert, Helmut and Klein, Dagmar and Freimuth, Herbert and Baumann, M{\´i}chael and Egersd{\"o}rfer, Stefan and Bruhns, Otto T. and Meier, Alexander and Raja, Kashif}, title = {Technologies for Haptic Systems in Telemedicine}, series = {Integration of Health Telematics into Medical Practice}, booktitle = {Integration of Health Telematics into Medical Practice}, editor = {Nerlich, Michael and Sch{\"a}chinger, Ulrich}, publisher = {IOS Press}, doi = {10.3233/978-1-60750-941-7-83}, pages = {83 -- 93}, abstract = {The ability to image the elastic properties of tissue is potentially useful in a variety of applications. The field of elastic imaging has grown in response to the Potential use of such information in medical diagnosis. Real time ultrasound elastography represents a recent development in determining strain and elasticity distributions. Nevertheless, commonly used imaging techniques rely on the interpretation of two dimensional visual data displayed on a video screen. In reality however, physicians often prefer tactile exploration making the simultaneous portrayal of both video and haptic information most desirable. Since the 1970's many alphanumeric to tactile data conversion methods have been investigated, mainly with the ultimate aim of assisting the blind. More recently, interest has been directed toward the display of pictures on haptically explorable surfaces - Tactile imaging. Such a system would allow surgeons to examine hard sectors contained within soft tissue, and thereby assist in operations held remotely. The expansion of ultrasound elastography to 3D formats would mean the ability to haptically explore regions of the body normally inaccessible to human hands. For three-dimensional imaging the acquisition of sequential tomographic slices using Elastography, combined with image segmentation, enables the reconstruction, quantification and visualisation of tumour volumes. In a collaborative project between four research Institutes, the aim is to produce a prototype three dimensional tactile displays comprising electrically switchable micromachined cells, whose mechanical moduli are governed by phase changes experienced by electrorheological and/or magnetorheological fluids. This will be integrated with a sensory ultrasonic elastography in order to present the human fingers with controllable surfaces capable of emulating biological tissue, muscle and bone.}, language = {en} } @article{MonkmanEgersdoerferMeieretal., author = {Monkman, Gareth J. and Egersd{\"o}rfer, Stefan and Meier, Alexander and B{\"o}se, Holger and Baumann, Michael and Ermert, Helmut and Kahled, W. and Freimuth, Herbert}, title = {Technologies for Haptic Displays in Teleoperation}, series = {Industrial Robot}, volume = {30}, journal = {Industrial Robot}, number = {6}, publisher = {Emerald}, issn = {0143-991x}, doi = {10.1108/01439910310506792}, pages = {525 -- 530}, abstract = {Since the 1960s many alphanumeric to tactile data conversion methods have been investigated, mainly with the ultimate aim of assisting the blind. More recently, interest has been directed toward the display of pictures on haptically explorable surfaces - tactile imaging - for a range of medical, remote sensing and entertainment purposes. This paper examines the technologies which have been utilised for haptically explorable tactile displays over the past three decades, focussing on those which appear commercially viable in the immediate future.}, language = {en} } @inproceedings{KhaledBruhnsReichlingetal., author = {Khaled, W. and Bruhns, Otto T. and Reichling, S. and B{\"o}se, Holger and Baumann, Michael and Monkman, Gareth J. and Egersd{\"o}rfer, Stefan and Meier, Alexander and Klein, Dagmar and Freimuth, Herbert and Ermert, Helmut}, title = {A haptic system for virtual reality applications based on ultrasound elastography and electrorheological fluids}, series = {Acoustical Imaging (ACIM)}, volume = {27}, booktitle = {Acoustical Imaging (ACIM)}, publisher = {Springer}, address = {Dordrecht}, isbn = {978-90-481-6652-7}, issn = {0270-5117}, doi = {10.1007/978-1-4020-2402-3_85}, pages = {667 -- 674}, abstract = {Mechanical properties of biological tissue represent important diagnostic information and are of histological and pathological relevance. Malignant tumors are significantly stiffer and more immobile than surrounding healthy tissue. Hard calcifications in vessels occur due to arteriosclerosis. The problem is, that such information is usually not available or can only be obtained by manual palpation, which is subjective and limited in sensitivity. It requires intuitive assessment and does not allow quantitative documentation. Unfortunately, none of the established medical imaging equipment such as magnetic resonance imaging (MRI) or X-ray computed tomography (CT) can provide direct measure of tissue elasticity. On the one hand a suitable sensor is required for quantitative measurement of mechanical tissue properties. On the other hand there is also some need for a realistic haptic display of such tissue properties. Suitable actuator arrays with high spatial resolution acting in real time are required. A haptic sensor actuator system is presented in this paper including a sensitive sensor part and an actuator array for different applications. The mechanical consistency of an object is to be locally specified using a sensor system and represented perceptibly in a remote position on an actuator system for the user. The sensor system uses ultrasound (US) elastography, whereas the actuator array is based on electrorheological (ER) fluids.}, language = {en} } @inproceedings{KhaledBruhnsReichlingetal., author = {Khaled, W. and Bruhns, Otto T. and Reichling, S. and B{\"o}se, Holger and Baumann, Michael and Monkman, Gareth J. and Egersd{\"o}rfer, Stefan and Meier, Alexander and Klein, Dagmar and Freimuth, Herbert and Ermert, Helmut}, title = {A haptic sensor-actuator-system based on ultrasound elastography and electrorheological fluids for virtual reality applications in medicine}, series = {CARS 2003 : computer assisted radiology and surgery ; proceedings of the 17th International Congress and Exhibition London, June 25 - 28, 2003}, booktitle = {CARS 2003 : computer assisted radiology and surgery ; proceedings of the 17th International Congress and Exhibition London, June 25 - 28, 2003}, publisher = {Elsevier}, address = {Amsterdam}, pages = {1354}, abstract = {Mechanical properties of biological tissue represent important diagnostic information and are of histological relevance (hard lesions, "nodes" in organs: tumors; calcifications in vessels: arteriosclerosis). The problem is, that such information is usually obtained by digital palpation only, which is limited with respect to sensitivity. It requires intuitive assessment and does not allow quantitative documentation. A suitable sensor is required for quantitative detection of mechanical tissue properties. On the other hand, there is also some need for a realistic mechanical display of those tissue properties. Suitable actuator arrays with high spatial resolution and real-time capabilities are required operating in a haptic sensor actuator system with different applications. The sensor system uses real time ultrasonic elastography whereas the tactile actuator is based on electrorheological fluids. Due to their small size the actuator array elements have to be manufactured by micro-mechanical production methods. In order to supply the actuator elements with individual high voltages a sophisticated switching and control concept have been designed. This haptic system has the potential of inducing real time substantial forces, using a compact lightweight mechanism which can be applied to numerous areas including intraoperative navigation, telemedicine, teaching, space and telecommunication.}, language = {en} } @article{KhaledErmertBruhnsetal., author = {Khaled, W. and Ermert, Helmut and Bruhns, Otto T. and Reichling, S. and B{\"o}se, Holger and Baumann, Michael and Monkman, Gareth J. and Egersd{\"o}rfer, Stefan and Meier, Alexander and Klein, Dagmar and Freimuth, Herbert}, title = {Haptic sensor-actuator-system based on ultrasound elastography and electrorheological fluids for virtual reality applications in medicine}, series = {Studies in health technology and informatics, Medicine Meets Virtual Reality (MMVR)}, volume = {11}, journal = {Studies in health technology and informatics, Medicine Meets Virtual Reality (MMVR)}, number = {94}, publisher = {IOS Press}, pages = {144 -- 150}, abstract = {Mechanical properties of biological tissue represent important diagnostic information and are of histological relevance (hard lesions, "nodes" in organs: tumors; calcifications in vessels: arteriosclerosis). The problem is, that such information is usually obtained by digital palpation only, which is limited with respect to sensitivity. It requires intuitive assessment and does not allow quantitative documentation. A suitable sensor is required for quantitative detection of mechanical tissue properties. On the other hand, there is also some need for a realistic mechanical display of those tissue properties. Suitable actuator arrays with high spatial resolution and real-time capabilities are required operating in a haptic sensor actuator system with different applications. The sensor system uses real time ultrasonic elastography whereas the tactile actuator is based on electrorheological fluids. Due to their small size the actuator array elements have to be manufactured by micro-mechanical production methods. In order to supply the actuator elements with individual high voltages a sophisticated switching and control concept have been designed. This haptic system has the potential of inducing real time substantial forces, using a compact lightweight mechanism which can be applied to numerous areas including intraoperative navigation, telemedicine, teaching, space and telecommunication.}, language = {de} } @inproceedings{KhaledBruhnsReichlingetal., author = {Khaled, W. and Bruhns, Otto T. and Reichling, S. and B{\"o}se, Holger and Baumann, Michael and Monkman, Gareth J. and Egersd{\"o}rfer, Stefan and Meier, Alexander and Freimuth, Herbert and Tunayar, A. and Ermert, Helmut}, title = {A New Haptic Sensor Actuator System for Virtual Reality Applications in Medicine}, series = {Medical Image Computing and Computer-Assisted Intervention - MICCAI 2003: 6th International Conference, Montr{\´e}al, Canada, November 15-18, 2003, Proceedings}, booktitle = {Medical Image Computing and Computer-Assisted Intervention - MICCAI 2003: 6th International Conference, Montr{\´e}al, Canada, November 15-18, 2003, Proceedings}, publisher = {Springer}, isbn = {978-3540204626}, pages = {132 -- 140}, language = {en} } @article{KhaledBruhnsReichlingetal., author = {Khaled, W. and Bruhns, Otto T. and Reichling, S. and B{\"o}se, Holger and Baumann, Michael and Monkman, Gareth J. and Egersd{\"o}rfer, Stefan and Meier, Alexander and Klein, Dagmar and Freimuth, Herbert and Ermert, Helmut}, title = {A haptic system for virtual reality applications based on ultrasound elastography and electrorheological fluids}, series = {Acoustical Imaging}, journal = {Acoustical Imaging}, number = {27}, publisher = {Kluver Academic}, address = {Dordrecht \& New York}, doi = {10.1007/978-1-4020-2402-3_85}, pages = {667 -- 675}, language = {en} } @article{KleinFreimuthMonkmanetal., author = {Klein, Dagmar and Freimuth, Herbert and Monkman, Gareth J. and Egersd{\"o}rfer, Stefan and Meier, Alexander and B{\"o}se, Holger and Baumann, Michael and Ermert, Helmut and Bruhns, Otto T.}, title = {Electrorheological Tactile Elements}, series = {Mechatronics}, volume = {15}, journal = {Mechatronics}, number = {7}, publisher = {Pergamon}, address = {Oxford}, doi = {10.1016/j.mechatronics.2004.05.007}, pages = {883 -- 897}, abstract = {The use of ultrasound systems for medical examination and diagnosis is nothing new. The extension of ultrasound techniques for real time elastographic analysis purposes represents a more recent development. Nevertheless, as they stand all such techniques rely on the interpretation of two-dimensional visual data displayed on a video screen. In reality however, a medical doctor will make as much use of exploratory touch as he or she does vision, making the simultaneous portrayal of both video and tactile information most desirable [B{\"o}se H, Monkman GJ, Freimuth H, Ermert H. Haptisches Sensor-Aktor-System uaf der grundlage der Echtzeitelastographie sowie von elktro- und magnetorheologischen Materialien "HASASEM" [3]. BMBF Antrag 01 IR A14D, Oktober 2000]. This paper discusses the preliminary tests and basic design parameters for single tactels using electrorheological fluids. The final aim is to produce a prototype three-dimensional tactile display comprising electrically switchable micro-machined cells whose mechanical moduli are governed by phase changes experienced by electrorheological fluids. This will be integrated with the latest elastographic ultrasonic sensor systems in order to present the human fingers with controllable surfaces capable of emulating biological tissue, muscle and bone.}, language = {en} } @inproceedings{KraemerMottokMeier, author = {Kr{\"a}mer, Stefan and Mottok, J{\"u}rgen and Meier, Hans}, title = {Modifikation des Taskzustandsmodells des LLREF-Schedulers auf einem Dual-Core-Prozessor}, series = {Proceedings of the 2nd Embedded Software Engineering Congress, 8. bis 10. Dezember 2009, Sindelfingen}, booktitle = {Proceedings of the 2nd Embedded Software Engineering Congress, 8. bis 10. Dezember 2009, Sindelfingen}, pages = {628 -- 636}, language = {de} } @inproceedings{KraemerMottokMeier, author = {Kr{\"a}mer, Stefan and Mottok, J{\"u}rgen and Meier, Hans}, title = {Modifikation des Taskzustandsmodells des LLREF-Schedulers auf einem Dual-Core-Prozess}, series = {Proceedings of the 2nd Embedded Software Engineering Congress, 8. bis 10. Dezember 2009, Sindelfingen}, booktitle = {Proceedings of the 2nd Embedded Software Engineering Congress, 8. bis 10. Dezember 2009, Sindelfingen}, pages = {628 -- 636}, language = {de} } @inproceedings{KraemerMottokMeier, author = {Kr{\"a}mer, Stefan and Mottok, J{\"u}rgen and Meier, Hans}, title = {Osek-basierende Implementierung des LLREF-Scheduling-Algorithmus f{\"u}r eine Dual-Core-Architektur}, series = {2. Landshuter Symposium Mikrosystemtechnik, Tagungsband, 24. une 25. Februar 2010, Hochschule Landshut}, booktitle = {2. Landshuter Symposium Mikrosystemtechnik, Tagungsband, 24. une 25. Februar 2010, Hochschule Landshut}, pages = {343 -- 349}, language = {de} } @article{KraemerMottokMeier, author = {Kr{\"a}mer, Stefan and Mottok, J{\"u}rgen and Meier, Hans}, title = {Multi-Core Scheduling in Embedded Systemen, Teil 1}, series = {Hanser Automotive}, journal = {Hanser Automotive}, number = {1-2}, pages = {18 -- 22}, language = {en} } @article{KraemerMottokMeier, author = {Kr{\"a}mer, Stefan and Mottok, J{\"u}rgen and Meier, Hans}, title = {Multi-Core Scheduling in Embedded Systemen, Teil 2}, series = {Hanser Automotive}, journal = {Hanser Automotive}, number = {3-4}, pages = {23 -- 25}, language = {en} } @article{KraemerMottokMeier, author = {Kr{\"a}mer, Stefan and Mottok, J{\"u}rgen and Meier, Hans}, title = {Multi-Core Scheduling in Embedded Systemen, Teil 3}, series = {Hanser Automotive}, journal = {Hanser Automotive}, number = {5-6}, pages = {14 -- 16}, language = {en} } @inproceedings{RaabKraemerMottoketal., author = {Raab, Peter and Kr{\"a}mer, Stefan and Mottok, J{\"u}rgen and Meier, Hans and Racek, Stanislav}, title = {Safe software processing by concurrent execution in a real-time operating system}, series = {16th International Conference on Applied Electronics (AE 2011), 2011, Pilsen, Czech Republic}, booktitle = {16th International Conference on Applied Electronics (AE 2011), 2011, Pilsen, Czech Republic}, pages = {315 -- 319}, abstract = {The requirements for safety-related software systems increases rapidly. To detect arbitrary hardware faults, there are applicable coding mechanism, that add redundancy to the software. In this way it is possible to replace conventional multi-channel hardware and so reduce costs. Arithmetic codes are one possibility of coded processing and are used in this approach. A further approach to increase fault tolerance is the multiple execution of certain critical parts of software. This kind of time redundancy is easily realized by the parallel processing in an operating system. Faults in the program flow can be monitored. No special compilers, that insert additional generated code into the existing program, are required. The usage of multi-core processors would further increase the performance of such multi-channel software systems. In this paper we present the approach of program flow monitoring combined with coded processing, which is encapsulated in a library of coded data types. The program flow monitoring is indirectly realized by means of an operating system.}, language = {en} } @inproceedings{HerboldReindlMeieretal., author = {Herbold, Florian and Reindl, Andrea and Meier, Hans and Niemetz, Michael and Kr{\"a}mer, Stefan}, title = {Secure Software Updates: Challenges and Solutions for Embedded IoT Systems}, series = {Proceedings of the 9th Embedded Systems Workshop: July 1-3, 2021 Horomerice, Czech Republic}, booktitle = {Proceedings of the 9th Embedded Systems Workshop: July 1-3, 2021 Horomerice, Czech Republic}, editor = {Kub{\´a}tov{\´a}, Hana and Fišer, Petr and Boreck{\´y}, Jaroslav}, isbn = {978-80-01-06858-8}, pages = {5 -- 13}, abstract = {The invention of the internet made the development of intelligent networking of millions of embedded systems possible. This enabled smart buildings, power grids and cities as well as applications in the fields of health, agriculture and industry. These systems frequently perform safety-critical applications and operations. This makes it urgent to protect these sensible systems as effectively as possible. Especially firmware updates are often the weak point in the systems. If unauthorised persons gain access to the system during the update, malware can be injected or sensitive data can be read and stolen. This paper describes the challenges of secure firmware updates. To protect an embedded system from potential attackers, the concepts integrity, authenticity and confidentiality have to be adhered during the update process. Otherwise, there is an increased risk of modifying or reverse engineering the firmware image. Likewise, inadequately protected software can enable the installation of third-party firmware as well as the installation of firmware on a third-party system. Threat prevention is presented with solutions derived from functional safety and IT security. Aspects of protection against errors in the transmission of updates and against attacks aiming to compromise the system are explained. Finally, a possible sequence of a secure update process is examined in detail for a real embedded system implementation. For this purpose, the preparation, transmission and installation of a firmware update in the bootloader are discussed}, language = {en} } @inproceedings{BlankBrunnerFuhrmannetal., author = {Blank, M. and Brunner, Stefan and Fuhrmann, Thomas and Meier, Hans and Niemetz, Michael}, title = {Embedded Linux in engineering education}, series = {2015 IEEE Global Engineering Education Conference (EDUCON), 18-20 March 2015, Tallinn, Estonia}, booktitle = {2015 IEEE Global Engineering Education Conference (EDUCON), 18-20 March 2015, Tallinn, Estonia}, publisher = {IEEE}, doi = {10.1109/EDUCON.2015.7095964}, pages = {145 -- 150}, abstract = {With the availability of cost effective embedded Linux solutions and the increasing complexity of embedded devices because of growing calculation power and communication demand, Linux is getting increasingly interesting as an operating system for the design of embedded control solutions. This is the case for almost all technical applications in electrical engineering like energy distribution systems, high level communication, signal processing or industrial automation. In the engineering master courses at the OTH Regensburg, a lecture is offered introducing students to Linux with a strong focus on embedded applications. This paper describes the concept of the lecture including the laboratory set up and gives some examples of embedded Linux projects performed by students.}, language = {en} } @article{ReindlZhengSchwarzetal., author = {Reindl, Klaus and Zheng, Yuanhang and Schwarz, Andreas and Meier, Stefan and Maas, Roland and Sehr, Armin and Kellermann, Walter}, title = {A stereophonic acoustic signal extraction scheme for noisy and reverberant environments}, series = {Computer Speech and Language}, volume = {27}, journal = {Computer Speech and Language}, number = {3}, publisher = {Elsevier}, doi = {10.1016/j.csl.2012.07.011}, pages = {726 -- 745}, abstract = {In this contribution, a novel two-channel acoustic front-end for robust automatic speech recognition in adverse acoustic environments with nonstationary interference and reverberation is proposed. From a MISO system perspective, a statistically optimum source signal extraction scheme based on the multichannel Wiener filter (MWF) is discussed for application in noisy and underdetermined scenarios. For free-field and diffuse noise conditions, this optimum scheme reduces to a Delay \& Sum beamformer followed by a single-channel Wiener postfilter. Scenarios with multiple simultaneously interfering sources and background noise are usually modeled by a diffuse noise field. However, in reality, the free-field assumption is very weak because of the reverberant nature of acoustic environments. Therefore, we propose to estimate this simplified MWF solution in each frequency bin separately to cope with reverberation. We show that this approach can very efficiently be realized by the combination of a blocking matrix based on semi-blind source separation ('directional BSS'), which provides a continuously updated reference of all undesired noise and interference components separated from the desired source and its reflections, and a single-channel Wiener postfilter. Moreover, it is shown, how the obtained reference signal of all undesired components can efficiently be used to realize the Wiener postfilter, and at the same time, generalizes well-known postfilter realizations. The proposed front-end and its integration into an automatic speech recognition (ASR) system are analyzed and evaluated in noisy living-room-like environments according to the PASCAL CHiME challenge. A comparison to a simplified front-end based on a free-field assumption shows that the introduced system substantially improves the speech quality and the recognition performance under the considered adverse conditions.}, language = {de} } @inproceedings{LegrandBoeseErmertetal., author = {Legrand, Virginie and B{\"o}se, Holger and Ermert, Helmut and Freimuth, Herbert and Baumann, Michael and Egersd{\"o}rfer, Stefan and Meier, Alexander and Dragoi, Daniel}, title = {Technologien f{\"u}r haptische Systeme in der Informations{\"u}bertragung}, series = {IAFW Tagung - Lengenfeld, Mai 2003}, booktitle = {IAFW Tagung - Lengenfeld, Mai 2003}, language = {de} }