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IEEE Journal on Indoor and Seamless Positioning and Navigation 2025年 3卷 81-104页

作者： Ott, Felix Heublein, Lucas Feigl, Tobias Rugamer, Alexander Mutschler, Christopher Self-Learning System group within the Machine Intelligence Department at the Fraunhofer Institute for Integrated Circuits IIS Nurnberg90411 Germany Localization and Networking Division at the Fraunhofer Institute for Integrated Circuits IIS Nurnberg90411 Germany Satellite-based Localization Systems ¨ Department at the Fraunhofer Institute for Integrated Circuits IIS Nurnberg90411 Germany

Jamming devices pose a significant threat as they disrupt signals from the global navigation satellite system (GNSS) and thus compromise the accuracy and robustness of positioning systems. The detection of anomalies in frequency snapshots is essential to effectively counteract these interferences. Furthermore, the ability to adapt to diverse and previously unseen interference characteristics is critical to ensuring the reliability of GNSS in real-world applications. In this paper, we propose a fewshot learning (FSL) approach to adapt to new classes of interference. We employ pairwise learning techniques, including triplet and quadruplet loss functions, during the training process to enhance the latent representation. In addition, we conducted a benchmark evaluation of stateof-the-art triplet learning methodologies utilizing GNSS datasets. Our method incorporates quadruplet selection, allowing the model to learn representations from various classes of positive and negative interference. Moreover, our quadruplet variant selects pairs based on aleatoric and epistemic uncertainty, facilitating differentiation between similar classes. We evaluated all methods using a publicly available indoor GNSS dataset collected in controlled environments characterized by various multipath effects, and using a dataset obtained from a highway bridge spanning a real-world German highway. Furthermore, we record and publish a second dataset from a highway featuring eight interference classes, in which our FSL method utilizing quadruplet loss demonstrates superior performance in jammer classification accuracy, achieving a rate of 97.66%. © 2023 CCBY.

关键词： Interference Global navigation satellite system Jamming Adaptation models Road transportation Location awareness integrated circuits Accuracy Training Navigation

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Investigating the Regularization of Deep Neural Networks for Affect Recognition with Relevance-Guided Local Explanations 19th

Investigating the Regularization of Deep Neural Networks f...

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19th International Conference on Artificial Intelligence: Methodology, systems, and Applications, AIMSA 2024

作者： Rieger, Ines Chair for Cognitive Systems University of Bamberg Bamberg Germany Fraunhofer Institute for Integrated Circuits IIS Erlangen Germany

ISBN: (纸本)9783031815416

Deep neural networks (DNNs) have demonstrated remarkable performance in various computer vision tasks. However, they face challenges that can inhibit their performance and transparency such as the learning of spurious patterns and a lack of explanatory power. This paper addresses these challenges in the domain of affect recognition, particularly for facial expressions. Our first contribution focuses on the integration of domain-specific knowledge into DNNs. To achieve this, we improve on a regularization method that constrains class co-occurrences, thereby outperforming existing state-of-the-art approaches. Our second contribution evaluates the impact of this regularization by employing an adapted explainable AI (XAI) method that incorporates expert knowledge. The results reveal that the regularization term encourages the learning of more generalized features. Consequently, XAI methods enhance the transparency of DNNs, contributing to the development of more reliable AI systems. © The Author(s), under exclusive license to Springer Nature Switzerland AG 2025.

关键词： Deep Neural Networks Explainable AI Regularization

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Exploratory Data Analysis of Time Series Using Pre-segmented Clustering 26th

Exploratory Data Analysis of Time Series Using Pre-segmente...

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26th International Conference on Information Integration and Web Intelligence, iiWAS 2024

作者： Jain, Vineeta Huang, Zihao Richter, Anna Wetzker, Ulf Frotzscher, Andreas Fraunhofer Institute for Integrated Circuits Division Engineering of Adaptive Systems EAS Dresden Germany Technische Universität Dresden Dresden Germany

ISBN: (纸本)9783031780899

Time series clustering is an unsupervised method of organizing homogeneous time series in groups based on certain similarity criteria. As a result, it can be an essential step in Exploratory Data Analysis (EDA), especially for complex time series data. This applies specifically to industrial datasets for applications like predictive maintenance, energy consumption, etc., due to the heterogeneity and peculiarity of collected data sets. Understanding the underlying trends and patterns in such datasets could help strategize advanced analysis methods such as forecasting, regression testing, etc. In this paper, we present a case study on a real-world energy consumption dataset of 4G cells, where we perform a pre-segmented clustering based EDA to uncover hidden insights about the data. The empirical study demonstrates that performing pre-segmented clustering based EDA enhances data interpretation by revealing prevalent and infrequent patterns, empowering users to refine analyses such as prediction more precisely, leading to performance improvement. © The Author(s), under exclusive license to Springer Nature Switzerland AG 2025.

关键词： Data assimilation

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Two Differential Wideband SIW-to-RWG Transitions for Thin Single Layer Substrates With Additional Tapering for D-Band Applications

Two Differential Wideband SIW-to-RWG Transitions for Thin Si...

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2025 IEEE Radio and Wireless Symposium, RWS 2025

作者： Braun, Tobias T. Romstadt, Justin Hansen, Steffen Schweer, Christian Pohl, Nils Institute for Integrated Systems Ruhr University Bochum Bochum Germany Integrated Circuits and Sensor Systems Fraunhofer FHR Wachtberg Germany Comfort Electronics Kostal Automobil Elektrik GmbH & Co. KG Dortmund Germany

ISBN: (纸本)9798350377743

Rectangular waveguides (RWGs) are the standard interface above 110 GHz, starting with the D-Band. Thus, transitions to connect integrated circuits and components, offering a low insertion loss across the complete waveguide band are required. This paper presents the design of such transitions from an RWG to a differential microstrip transmission line. Apart from a multi-section stepped impedance transformer it proposes the use of an additional substrate taper at the first step. This design is verified via a realization in two different single layer substrates with thick metal cladding. Those are the Rogers RT/duroid 5880 and RO3003, respectively. Measurement results show return losses above 15 dB and 12 dB, respectively. The best achieved insertion loss equals 0.6 dB, while the corresponding 3 d B bandwidths cover more than the entire D-band. © 2025 IEEE.

关键词： Insertion losses

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Two Differential Wideband SIW-to-RWG Transitions for Thin Single Layer Substrates With Additional Tapering for D-Band Applications

Two Differential Wideband SIW-to-RWG Transitions for Thin Si...

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IEEE Radio and Wireless Symposium (RWS formerly RAWCON)

作者： Tobias T. Braun Justin Romstadt Steffen Hansen Christian Schweer Nils Pohl Institute for Integrated Systems Ruhr University Bochum Bochum Germany Integrated Circuits and Sensor Systems Fraunhofer FHR Wachtberg Germany Comfort Electronics Kostal Automobil Elektrik GmbH & Co. KG Dortmund Germany

ISBN: (数字)9798350377743

ISBN: (纸本)9798350377750

Rectangular waveguides (RWGs) are the standard interface above 110 GHz, starting with the D-Band. Thus, transitions to connect integrated circuits and components, offering a low insertion loss across the complete waveguide band are required. This paper presents the design of such transitions from an RWG to a differential microstrip transmission line. Apart from a multi-section stepped impedance transformer it proposes the use of an additional substrate taper at the first step. This design is verified via a realization in two different single layer substrates with thick metal cladding. Those are the Rogers RT/duroid 5880 and RO3003, respectively. Measurement results show return losses above 15 dB and 12 dB, respectively. The best achieved insertion loss equals 0.6 dB, while the corresponding $\mathbf{3 d B}$ bandwidths cover more than the entire D-band.

关键词： Wireless communication Claddings Metals Insertion loss Transmission line measurements Transformers Loss measurement Impedance Substrates Standards

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Performance Tradeoff Between Overhead and Achievable SNR in RIS Beam Training

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IEEE Transactions on Wireless Communications 2025年

作者： Laue, Friedemann Jamali, Vahid Schober, Robert Institute for Digital Communications Erlangen91058 Germany Fraunhofer Institute for Integrated Circuits IIS Division Communication Systems Germany Technical University of Darmstadt Department of Electrical Engineering and Information Technology Darmstadt64283 Germany

Efficient beam training is the key challenge in the codebook-based configuration of reconfigurable intelligent surfaces (RISs) because the beam training overhead can have a strong impact on the achievable system performance. In this paper, we study the performance tradeoff between overhead and achievable signal-to-noise ratio (SNR) in RIS beam training while taking into account the size of the targeted coverage area, the RIS response time, and the delay for feedback transmissions. Thereby, we consider three common beam training strategies: full search (FS), hierarchical search (HS), and tracking-based search (TS). Our analysis shows that the codebook-based illumination of a given coverage area can be realized with wide- or narrow-beam designs, which result in two different scaling laws for the achievable SNR. Similarly, there are two regimes for the overhead, where the number of pilot symbols required for reliable beam training is dependent on and independent of the SNR, respectively. Based on these insights, we reveal that the overhead for FS beam training can be significantly reduced by employing large RISs and wide beams. Moreover, we show that, depending on the RIS response time, feedback delay, and codebook size, FS beam training may outperform HS beam training. In addition, we derive an upper bound on the user velocity for which the overhead is generally negligible. Finally, we present numerical simulation results that verify our theoretical analysis. In particular, our results confirm the existence of the proposed SNR scaling laws and overhead regimes, demonstrate the benefits of wide beams and large RISs, reveal that fast RISs can lead to negligible overhead for FS beam training, and show that large feedback delays can significantly reduce the performance for HS beam training. © 2002-2012 IEEE.

关键词： Risk management

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SIMULTANEOUS INSITU MEASUREMENT OF FILM THICKNESS AND TEMPERATURE BY USING MULTIPLE WAVELENGTHS PYROMETRIC INTERFEROMETRY (MWPI)

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IEEE TRANSACTIONS ON SEMICONDUCTOR MANUFACTURING 1993年第2期6卷 112-118页

作者： BOEBEL, FG MOLLER, H Fraunhofer Institute of Integrated Circuits and Systems Erlangen Germany

Film thickness and temperature are two of the most important quantities in semiconductor manufacturing. They play a fundamental role in many standard production techniques like chemical vapor deposition (CVD, LPCVD, PECVD), thermal oxidation and diffusion. They are especially important for more recently developed technologies like molecular beam epitaxy (MBE), metal organic MBE (MOMBE), metal organic CVD (MOCVD), chemical beam epitaxy (CBE), etc. In this paper, an optical in situ method for simultaneous film thickness and temperature measurements-named Multiple Wavelengths Pyrometric Interferometry (MWPI)-is introduced, which is capable of high resolution (up to 0.1 nm for thickness and 0.025 K for temperature) and for real time data evaluation. It can be used for process control as well as in situ quality inspection without time delay or additional handling mechanisms and is suitable for monitoring single films as well as multilayer structures. MWPI is insensitive to vibration, rotation and misalignment of the wafer. Due to its optical basis it is also insensitive to hostile environments like high temperature and/or chemical reactive gases. The physical basis of MWPI is outlined as well as the necessary steps of the evaluation procedure. The simultaneous in situ MWPI film thickness and temperature measurement during the thermal oxidation of Si is presented. The potential technical impact of MWPI on automation, reliability and long term performance of semiconductor manufacturing is discussed.

关键词： Thickness measurement Molecular beam epitaxial growth Optical films Chemical vapor deposition Optical interferometry Semiconductor films Chemical technology Temperature measurement Semiconductor device manufacture Production

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CHARACTERIZATION AND IMPROVEMENT OF GAAS HEMT ANALOG SWITCHES FOR SAMPLED-DATA APPLICATIONS

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IEEE JOURNAL OF SOLID-STATE circuits 1994年第7期29卷 844-850页

作者： FENG, S SEITZER, D Fraunhofer Institute of Integrated Circuits and Systems Erlangen Germany

This paper presents design consideration an experimental comparison of GaAs HEMT analog switches for high-speed and high-precision sampled-data applications. At first, basic pass-transistor switches fabricated in a 0.5-mum GaAs HEMT technology are measured for characterization of transient errors induced due to clock-feedthrough and charge transfer. In order to improve the switch dynamic performances, a dual dummy transistor compensation technique is used and related driver circuitry is developed. On-wafer measurements demonstrate that the improved switch provides a significant reduction of the transient errors, a reasonable dynamic range, and a high isolation. The switch with a 0.53 pF load capacitor achieves a total harmonic distortion below -55 dB and -38 dB at 10 MHz and 1.0 GHz clock frequency, respectively.

关键词： integrated circuits ANALOG SWITCHES GALLIUM ARSENIDE

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Identification of dynamic models for the short-term temperature prediction in a single room

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IFAC-PapersOnLine 2018年第2期51卷 79-84页

作者： Paschke, Fabian Zaiczek, Tobias Fraunhofer IIS/EAS Fraunhofer Institute for Integrated Circuits Division Engineering of Adaptive Systems Dresden Germany

This contribution illustrates an approach for the generation of a linear dynamic discrete time model for the short term prediction of the room temperature in a single conference room. The model is extracted from recorded measurement data by means of system identification. After a brief description of the considered room and the modeling approach the model is validated by statistical analysis and by its prediction performance. © 2018

关键词： Model predictive control

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Microelectronic systems: circuits, systems and Applications 2011°

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2011年

作者： Janina Heppner

ISBN: (数字)9783642230714

ISBN: (纸本)3642230709

This book is dedicated to Prof. Dr. Heinz Gerhuser on the occasion of his retirement both from the position of Executive Director of the fraunhofer institute for integrated circuits IIS and from the Endowed Chair of Information Technologies with a Focus on Communication Electronics (LIKE) at the Friedrich-Alexander-Universitt Erlangen-Nrnberg. Heinz Gerhuser's vision and entrepreneurial spirit have made the fraunhofer IIS one of the most successful and renowned German research institutions. He has been Director of the fraunhofer IIS since 1993, and under his leadership it has grown to become the largest of Germany's 60 fraunhofer institutes, a position it retains to this day, currently employing over 730 staff. Likely his most important scientific as well as application-related contribution was his pivotal role in the development of the mp3 format, which would later become a worldwide success. The contributions to this Festschrift were written by both fraunhofer IIS staff and external project team members in appreciation of Prof. Dr. Gerhuser's lifetime academic achievements and his inspiring leadership at the fraunhofer IIS. The papers reflect the broad spectrum of the institute's research activities and are grouped into sections on circuits, information systems, visual computing, and audio and multimedia. They provide academic and industrial researchers in fields like signal processing, sensor networks, microelectronics, and integrated circuits with an up-to-date overview of research results that have a huge potential for cutting-edge industrial applications.

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