@article{64370, author = {{Lenz, Marcel and Krug, Robin and Gerhardt, Nils Christopher and Schmieder, Kirsten and Dillmann, Christopher and Stroop, Ralf and Welp, H.}}, journal = {{Journal of biomedical optics}}, number = {{7}}, pages = {{071205}}, title = {{{Automated differentiation between meningioma and healthy brain tissue based on optical coherence tomography ex vivo images using texture features}}}, doi = {{10.1117/1.jbo.23.7.071205}}, volume = {{23}}, year = {{2018}}, } @inproceedings{64369, author = {{Besaga, Vira and Gerhardt, Nils Christopher and Hofmann, Martin R. and Maksimyak, Peter P.}}, booktitle = {{Thirteenth International Conference on Correlation Optics}}, title = {{{A direct-view customer-oriented digital holographic camera}}}, doi = {{10.1117/12.2304923}}, year = {{2018}}, } @inproceedings{15952, abstract = {{Arbitrary sampling rate conversion has already received considerable attention in the past, but still lacks an equivalent representation of the effective time-dilation process in the block frequency domain. Good sampling rate converters in the time domain have been known, for instance, in terms of time-varying 'Sinc' or fixed 'Farrow' polynomial filters. The former can deliver nearly exact conversion at high complexity, while the latter has pronounced computational efficiency with limited accuracy. Only recently, it was shown that a composite 'polyphase Farrow' form with high resampling precision can be implemented with quasi-fixed filters that operate at the input sampling rate. We therefore propose to capitalize from that fixed-filter architecture in that we translate the polyphase-Farrow filters into an equivalent FFT-based overlap-save form. Experimental evaluation and comparison with other state-of-the art frequency-domain approaches then proves currently the best price-performance ratio of the proposed algorithm. It is thus an ideal candidate for the new framework of acoustic sensor networks that critically rests upon fast and accurate alignment of autonomous sampling processes.}}, author = {{Schmalenstroeer, Joerg and Chinaev, Aleksej and Enzner, Gerald}}, booktitle = {{Speech Communication; 13th ITG-Symposium}}, issn = {{null}}, pages = {{1--5}}, title = {{{Fast and Accurate Audio Resampling for Acoustic Sensor Networks by Polyphase-Farrow Filters with FFT Realization}}}, year = {{2018}}, } @inproceedings{24193, abstract = {{A complete system analysis for an integrated passive RFID transponder designed at 5.8 GHz range is presented, and a comprehensive set of design concerns for the rectifier circuit as the core of the harvesting block is also discussed. The system analysis is complemented by transistor-level design and simulation of harvesting circuits in a commercial 65 nm CMOS technology. A differential drive rectifier (DDR) has been selected as the most efficient harvesting topology for microwave frequency applications, which works at very low input power levels. The circuit was designed and simulated including chip layout parasitics and antenna matching circuitry. Considering the power budget of the tag chip, a power conversion efficiency of roughly 68.4% is achieved in simulation for an input RF power of around -11.26dBm.}}, author = {{Haddadian, Sanaz and Scheytt, Christoph}}, booktitle = {{Electromagnetics Research Symposium}}, issn = {{1559-9450 }}, location = {{ Toyama, Japan}}, title = {{{Wireless Energy Harvesting in RFID Applications at 5.8 GHz ISM Band, a System Analysis}}}, doi = {{10.23919/PIERS.2018.8597594}}, volume = {{40th}}, year = {{2018}}, } @inproceedings{58666, abstract = {{In this paper, a questionnaire-based survey on the use of online videos by undergraduate engineering students for study-related purposes is presented. Over the last few years, a large number of instructional videos has been uploaded to websites such as YouTube. Due to the widespread distribution of high-speed internet connections and (mobile) devices, such as smartphones or laptops, which are nowadays routinely used by students, online videos are also frequently used in higher education. While much research on this subject focuses on Massive Open Online Courses (MOOCs) or flipped classroom approaches, this survey examines use of videos for self-study, complementary to traditional face-to-face courses. Furthermore, we analyze the acceptance of a characteristic video production style, which uses specific 3D animations to clarify complex connections between technical and mathematical aspects. The results indicate extensive use of short videos which address subjects that are particularly difficult for the students. This survey can help educators to develop an impression of current video use by undergraduate engineering students. In this paper, a questionnaire-based survey on the use of online videos by undergraduate engineering students for study-related purposes is presented. Especially over the last few years, a large number of instructional videos has been uploaded to websites such as YouTube. Due to the widespread distribution of high-speed internet connections and (mobile) devices, such as smartphones or laptops, which are nowadays routinely used by students, online videos are also frequently used in higher education. While much research on this subject focuses on Massive Open Online Courses (MOOCs) or flipped classroom approaches, this survey examines usage behavior concerning the apparently much more common use of videos for self-study, complementary to traditional face-to-face courses. Furthermore, we analyze the acceptance of a characteristic video production style using specific 3D animations to clarify complex connections between technical and mathematical aspects. The results indicate that short videos addressing subjects that are particularly difficult for the students are extensively used. Additionally, this survey can help educators to develop a realistic understanding of current video use by undergraduate engineering students.}}, author = {{Hennig, Markus and Mertsching, Bärbel}}, booktitle = {{Proceedings of the 4th International Conference on Higher Education Advances (HEAd'18)}}, publisher = {{Universitat Politècnica València}}, title = {{{Study-related Use of Instructional Videos by Undergraduate Engineering Students}}}, doi = {{10.4995/head18.2018.8207}}, year = {{2018}}, } @inproceedings{24185, abstract = {{In this poster, we present the first experimental results of our OFDM-based Vehicular VLC (V-VLC) prototype. Our Bit Error Rate (BER) measurements show that for lower Modulation and Coding Schemes (MCS), the performance of our hardware-setup roughly behaves the same as it does in simulation for AWGN channel. However, for higher order MCS with high PAPR, the BER performance gets degraded due to non-linear behavior of LEDs, and deviates further from AWGN performance as the MCS order is increased. The obtained results suggest that unlike RF-Communications, where the focus is usually towards linearity of the amplifiers, for V-VLC, linearity within the whole system is required to achieve optimal performance.}}, author = {{Koepe, Jörn and Kaltschmidt, Christian and Illian, Marvin and Puknat, Robert and Kneuper, Pascal and Wittemeier, Steffen and Memedi, Agon and Tebruegge, Claas and Amjad, Muhammad Sohaib and Kruse, Stephan and Kress, Christian and Scheytt, Christoph and Dressler, Falko}}, booktitle = {{2018 IEEE Vehicular Networking Conference (VNC)}}, publisher = {{IEEE}}, title = {{{First Performance Insights on Our Noval OFDM-based Vehicular VLC Prototype}}}, doi = {{10.1109/VNC.2018.8628322}}, year = {{2018}}, } @inproceedings{24190, abstract = {{We present a transmitter circuit to drive a commercial Light Emitting Diode (LED)-based headlight for automotive Visible Light Communication (VLC). Based on the design of the presented transmitter (TX), we provide a design methodology for VLC TXs and make it available as Open Hardware. Furthermore, a complete wireless VLC link is built using the GNU Radio signal processing tool chain and demonstrated on an Universal Software Radio Peripheral (USRP). The Total Harmonic Distortion (THD) of the system is below 5% for a wide input voltage range and the 1 dB compression point (P1dB) is at 1.02V, which makes the circuit attractive for more advanced modulation formates like Orthogonal Frequency Division Multiplexing (OFDM) or Pulse-Amplitude Modulation (PAM). }}, author = {{Kruse, Stephan and Kress, Christian and Memedi, Agon and Tebruegge, Claas and Amjad, Muhammad Sohaib and Scheytt, Christoph and Dressler, Falko}}, booktitle = {{ANALOG 2018 16. GMM/ITG-Fachtagung}}, location = {{Bürokomplex Campeon München/ Neubiberg}}, publisher = {{IEEE}}, title = {{{Design of an Automotive Visible Light Communications Link using a Off-The-Shelf LED Headlight}}}, year = {{2018}}, } @inproceedings{24215, abstract = {{Wireless Sensor Networks (WSN) consist of large number of distributed sensors nodes which are able to sense, read and transmit physical measurements such as temperature, humidity and pressure over wireless communication links. WSN nodes are often powered by batteries or can use energy harvesting methods from environmental energy sources. One of the major challenges in the design of WSN nodes is the high level of power dissipation for sensing, processing and communication. Operating at low-power levels reduces maintenance effort for periodic battery replacement or can even provide unlimited operation by means of energy harvesting. Since the communication process is the most power hungry process, ultra-low-power wireless communication is an enabler for network applications such as cyber-physical systems, Internet-of-Things and Industry 4.0 etc. Our research is based on Wake-up Receivers (WuR) architectures. Each of the WSN nodes contains a WuR which is always-on, listening for a wake-up signal from other nodes or the base station, and activating the node only when a wake-up signal is detected. By this scheme the communication with the base station becomes asynchronous, real-time and on-demand. Due to the centrally-coordinated, collision-free communication such WSNs can be scaled to very large node numbers. Designing always-on WuR at ultra-low-power dissipation levels makes the WSN nodes very energy efficient because they are only activated when a wake-up-signal is received. Additionally, the WuR must be robust to noise and co-channel interference in order to operate safely in parallel to other wireless systems. We investigate a novel radio architecture for the WuR using Linear Frequency Modulation (LFM) and passive analog signal processing by means of a Surface Acoustic Wave (SAW) correlator. The base station sends the required WSN node ID using LFM signal at 2.4 GHz. The node ID is encoded as chirp up or chirp down signal with chirping bandwidth of 80MHz. On the receiver side, the SAW chirp correlator demodulates the received LFM signal while suppressing other wireless signals. In order to achieve proper demodulation and high Signal-to-Noise Ratio (SNR), the SAW correlator is designed to behave like a Matched Filter (MF) which boosts up the SNR. After that the signal is amplified/detected by baseband amplifier stage, it is compared with the unique ID of the node, and the node's Wake up signal is asserted accordingly. Since the SAW correlator operates completely passive, the WuR can be implemented in a very energy-efficient way, without the need to use power hungry device such as Low Noise Amplifiers (LNA) or down conversion Local Oscillators (LO)}}, author = {{Abughannam, Saed and Scheytt, Christoph}}, booktitle = {{Kleinheubacher Tagung 2017}}, pages = {{47}}, title = {{{ Low-Power wake up receiver based on Surface Acoustic Wave Correlator}}}, year = {{2017}}, } @article{24216, abstract = {{In this article mixed analog/digital signal processing techniques based on parallel spread-spectrum sequencing (PSSS) and radio frequency (RF) carrier synchronization for ultra-broadband wireless communication are investigated on system and circuit level.}}, author = {{Scheytt, Christoph and Javed, Abdul Rehman and Bammidi, Eswara Rao and KrishneGowda, Karthik and Kallfass, Ingmar and Kraemer, Rolf}}, journal = {{Frequenz* Journal of RF-Engineering and Telecommunications}}, number = {{9-10}}, pages = {{399--414}}, title = {{{100 Gbps Wireless System and Circuit Design Using Parallel Spread-Spectrum Sequencing}}}, volume = {{71 }}, year = {{2017}}, } @inproceedings{24217, abstract = {{Parallel Sequence Spread Spectrum (PSSS) is a physical layer (PHY) baseband technology that is well suited for mixed-signal transceiver implementation for high data rate wireless communication systems. Mixed signal baseband realization allows for easier implementation of the channel equalization function and eliminates the need for high speed data converters. System design and architecture of a mixed signal baseband processor for 100 Gbps wireless communication is described that reduces the implementation complexity and results in a consequent reduction in power dissipation and chip area. An ultra-broadband analog correlator consisting of a four-quadrant multiplier and a fast resettable integrator using only NPN transistors was designed, fabricated, and measured. The correlator circuit is the core component of the receiver baseband. To the best knowledge of the authors, it is the fastest correlator circuit published so far.}}, author = {{Javed, Abdul Rehman and Scheytt, Christoph and Karthik, KrishneGowda and Kramer, Roland}}, booktitle = {{IEEE EUROCON 2017-17th International Conference on Smart Technologies}}, isbn = {{978-1-5090-3844-2}}, pages = {{228--233}}, title = {{{System design of a mixed signal PSSS transdeiver using a linear ultra-broadband analog correlator for the receiver baseband designed in 130nm SiGe BiCMOS technology}}}, doi = {{10.1109/EUROCON.2017.8011110}}, year = {{2017}}, } @misc{24218, abstract = {{ Die Erfindung betrifft eine Folge-Halte-Schaltung zum Konvertieren eines analogen Eingangssignals in ein digitales Ausgangssignal mit einer Haltekapazitätseinheit, mit einer Spannungsverstärkereinheit enthaltend einen Eingang, an dem ein analoges Eingangsspannungssignal anlegbar ist, und enthaltend einen Ausgang, der mit der Haltekapazitätseinheit verbunden ist, mit einer Arbeitspunkteinstelleinheit zur Steuerung der Spannungsverstärkereinheit, wobei an einem Eingang der Arbeitspunkteinstelleinheit ein Steuersignal anliegt, so dass in einem Folgebetrieb der Folge-Halte-Schaltung eine an dem Ausgang der Spannungsverstärkereinheit anliegendes Ausgangssignal einen an den Eingang der Spannungsverstärkereinheit anliegendes Eingangssignal folgt, und in einem Haltebetrieb der Folge-Halte-Schaltung das Ausgangssignal der Spannungsverstärkereinheit konstant ist, mit einer Taktsignalquelle zur Erzeugung einer Folge von einem Eingang der Arbeitspunkteinstelleinheit anliegenden Taktsignalen, wobei die Arbeitspunkteinstelleinheit elektrooptische Mittel zur Erzeugung des Steuersignals aufweist, dass die Taktsignalquelle als eine optische Taktsignalquelle ausgebildet ist, so dass als Taktsignal eine optische Impulsfolge mit hohen und tiefen Taktsignalen an den Eingang der Arbeitspunkteinstelleinheit anliegt. }}, author = {{Scheytt, Christoph}}, title = {{{Folge-Halte-Schaltung }}}, year = {{2017}}, } @inproceedings{24220, author = {{Adelt, Peer and Koppelmann, Bastian and Müller, Wolfgang and Mueller-Gritschneder, Daniel and Kleinjohann, Bernd and Scheytt, Christoph}}, booktitle = {{Tagungsband des Wissenschaftsforums Intelligente Technische Systeme}}, isbn = {{978-3-942647-88-5}}, publisher = {{Verlagsschriftenreihe des Heinz Nixdorf Instituts}}, title = {{{Automatisierte Fehlerinjektion zur Entwicklung sicherer Mikrocontrolleranwendungen auf der Basis virtueller Plattformen}}}, doi = {{10.17619/UNIPB/1-93}}, year = {{2017}}, } @book{24221, abstract = {{Das Wissenschaftsforum Intelligente Technische Systeme (WInTeSys) legt am 11. und 12. Mai 2017 in Paderborn den Schwerpunkt auf die Grundlagen und die Entwicklung intelligenter technischer Systeme im Kontext Industrie 4.0. Etwa 40 begutachtete hochkarätige Beiträge geben einen Überblick über Forschungsfelder, Technologien und Anwendungen. Die Veranstaltung bietet den Teilnehmerinnen und Teilnehmern eine ausgezeichnete Bühne für den Erfahrungsaustausch auf dem Weg in die Digitalisierung von Produkten und Produktionssystemen. »Das Besondere ist der Dialog von Hochschulforschung und industrieller Entwicklung, also das Aufeinandertreffen von »Science-Push« und »Application-Pull«. Die Beiträge spiegeln die hervorragende Vernetzung in der Region OWL und darüber hinaus wider«, sagt Veranstalter Prof. Jürgen Gausemeier (Heinz Nixdorf Institut, Universität Paderborn).}}, author = {{Gausemeier, Jürgen and Bodden, Eric and Dressler, Falko and Dumitrescu, Roman and Meyer auf der Heide, Friedhelm and Scheytt, Christoph and Trächtler, Ansgar}}, isbn = {{978-3-942647-88-5}}, publisher = {{Verlagsschriftenreihe des Heinz Nixdorf Instituts, Paderborn}}, title = {{{Wissenschaftsforum Intelligente Technische Systeme (WInTeSys)}}}, doi = {{10.17619/UNIPB/1-93}}, volume = {{369}}, year = {{2017}}, } @inproceedings{24223, abstract = {{This paper presents the design flow of using sampling technique for fault injection on sche- matic level. The parameters used in the docu- ment to calculate the likelihood could be modi- fied by using more realistic data from the fab. With the help of the fault simulator, the whole design flow of the fault effect simulation can be realized automatically.}}, author = {{Wu, Liang and Abughannam, Saed and Müller, Wolfgang and Scheytt, Christoph and Ecker, Wolfgang}}, booktitle = {{2nd Workshop on Resiliency in Embedded Electronic Systems (REES)}}, pages = {{68}}, title = {{{SPICE-Level Fault Injection with Likelihood Weighted Random Sampling - A Case Study}}}, year = {{2017}}, } @inproceedings{24224, author = {{Adelt, Peer and Koppelmann, Bastian and Müller, Wolfgang and Kleinjohann, Bernd and Scheytt, Christoph}}, booktitle = {{Design Automation and Testing in Europe (DATE), University Booth Interactive Presentation}}, title = {{{ANALISA - A Tool for Static Instruction Set Analysis}}}, year = {{2017}}, } @inproceedings{24225, author = {{Adelt, Peer and Koppelmann, Bastian and Müller, Wolfgang and Kleinjohann, Bernd and Scheytt, Christoph}}, booktitle = {{2nd Workshop on Resiliency in Embedded Electronic Systems (REES) }}, pages = {{44}}, title = {{{An Automatic Injection Framework for Safety Assessements of Embedded Software Binaries}}}, year = {{2017}}, } @article{24227, abstract = {{This work describes an electrical interferometer for contactless permittivity measurements working at 120 GHz. It was fabricated in a 130 nm SiGe process featuring an ft and fmax of 240 and 330 GHz. The on-chip system contains a 120 GHz VCO with a tuning range of 7 GHz featuring a divide-by-64 circuit to enable external PLL operation. The subsequent buffer provides 7 dBm of output power at 120 GHz. Additionally, the IC contains high-precision and high-resolution phase shifters based on a slow-wave transmission line approach with digital control for direct readout ability. A 120 GHz LNA with 17 dB gain and a power detector to provide DC output signals were realized on chip. It enables sample emulation capability by phase shift inducement in the measurement as well as a reference transmission line. In terms of phase detection, the system shows a sensitivity of 907.36 MHz/°.}}, author = {{Wessel, Jan and Schmalz, Klaus and Scheytt, Christoph and Kissinger, Dietmar}}, issn = {{1558-1764}}, journal = {{IEEE Microwave and Wireless Components Letters}}, number = {{2}}, pages = {{198--200}}, title = {{{A 120-GHz Electrical Interferometer for Contactless Permittivity Measurements With Direct Digital Read-Out}}}, doi = {{10.1109/LMWC.2017.2649384}}, volume = {{27}}, year = {{2017}}, } @article{3523, abstract = {{We numerically simulate the circular polarization ratio of the radar signal backscattered from a large-grain cometary coma and compare the simulation results with the radar measurements for seven comets. We apply the discrete dipole approximation method and a model of random irregular particles. Our results confirm water ice composition of the cm-sized chunks detected by the NASA Deep Impact space probe in the vicinity of the nucleus of Comet 103P/Hartley 2. The index of the power-law size distribution in this case can be constrained to the range n ≈ 3.3–4.3. For the other considered comets the circular polarization ratio can be reproduced with variations of the power index between 2 and 5.}}, author = {{Dogra, Shraddha and Grynko, Yevgen and Zubko, Evgenij and Förstner, Jens}}, issn = {{0004-6361}}, journal = {{Astronomy & Astrophysics}}, keywords = {{tet_topic_scattering}}, pages = {{A20}}, publisher = {{EDP Sciences}}, title = {{{Radar backscattering from a large-grain cometary coma: numerical simulation}}}, doi = {{10.1051/0004-6361/201730801}}, volume = {{608}}, year = {{2017}}, } @inbook{3743, abstract = {{Frequently, optical integrated circuits combine elements (waveguide channels, cavities), the simulation of which is well established through mature numerical eigenproblem solvers. It remains to predict the interaction of these modes. We address this task by a general, “Hybrid” variant (HCMT) of Coupled Mode Theory. Using methods from finite-element numerics, the properties of a circuit are approximated by superpositions of eigen-solutions for its constituents, leading to quantitative, computationally cheap, and easily interpretable models.}}, author = {{Hammer, Manfred}}, booktitle = {{Recent Trends in Computational Photonics}}, editor = {{Agrawal, Arti}}, isbn = {{978-3-319-55438-9}}, keywords = {{tet_topic_waveguide, tet_topic_numerics}}, pages = {{77--105}}, publisher = {{Springer}}, title = {{{Guided Wave Interaction in Photonic Integrated Circuits — A Hybrid Analytical/Numerical Approach to Coupled Mode Theory}}}, volume = {{204}}, year = {{2017}}, } @article{3828, abstract = {{The 3D implementation of a hybrid analytical/numerical variant of the coupled-mode theory is discussed. Eigenmodes of the constituting dielectric channels are computed numerically. The frequency-domain coupled-mode models then combine these into fully vectorial approximations for the optical electromagnetic fields of the composite structure. Following a discretization of amplitude functions by 1D finite elements, pro- cedures from the realm of finite-element numerics are applied to establish systems of linear equations for the then- discrete modal amplitudes. Examples substantiate the functioning of the technique and allow for some numerical assessment. The full 3D simulations are highly efficient in memory consumption, moderately demanding in com- putational time, and, in regimes of low radiative losses, sufficiently accurate for practical design. Our results include the perturbation of guided modes by changes of the refractive indices, the interaction of waves in parallel, horizontally or vertically coupled straight waveguides, and a series of crossings of potentially overlapping channels with fairly arbitrary relative positions and orientations.}}, author = {{Hammer, Manfred and Alhaddad, Samer and Förstner, Jens}}, issn = {{0740-3224}}, journal = {{Journal of the Optical Society of America B}}, keywords = {{tet_topic_waveguide, tet_topic_numerics}}, number = {{3}}, pages = {{613--624}}, publisher = {{The Optical Society}}, title = {{{Hybrid coupled-mode modeling in 3D: perturbed and coupled channels, and waveguide crossings}}}, doi = {{10.1364/josab.34.000613}}, volume = {{34}}, year = {{2017}}, }