2020

 nach oben zur Jahresübersicht

• Uwe Wagschal, Thomas Metz, Thomas Waldvogel, Bernd Becker, Linus Feiten, Samuel Weishaupt
  Das »Debat-O-Meter« als neues Tool in der E-Partizipation
  In: Demokratie im 21. Jahrhundert
  2020, Nomos, Seiten: 341 - 368, ISBN: 978-3-7489-2150-9

2019

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• Leonie Feldbusch, Felix Winterer, Johannes Gramsch, Linus Feiten, Bernd Becker
  Gamification in a Classroom Response System for Academic Teaching
  2019 11th International Conference on Computer Supported Education (CSEDU)
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  Kurzfassung

  The classroom response system SMILE (SMartphones In LEctures) is regularly used in academic lectures. Among other features, it enables lecturers to start quizzes that can be answered anonymously by students on their smartphones. This aims at both activating the students and giving them feedback about their understanding of the current content of the lecture. But even though many students use SMILE in the beginning of a course, the number of active participants tends to decrease as the term progresses. This paper reports the results of a study looking at incorporating gamification into SMILE to increase the students’ motivation and involvement. Game elements such as scores, badges and a leaderboard have been integrated paired with a post-processing feature enabling students to repeat SMILE quizzes outside of the lectures. The evaluations show that the gamification approach increased the participation in SMILE quizzes significantly.
• Uwe Wagschal, Thomas Waldvogel, Thomas Metz, Samuel Weishaupt, Linus Feiten, Bernd Becker, Kamal Singh
  Alle gegen Alle? Die Mehrpersonendebatte der kleinen Parteien in der Analyse
  In: Die Bundestagswahl 2017: Analysen der Wahl-, Parteien-, Kommunikations- und Regierungsforschung
  2019, en Wiesbaden, Seiten: 461 - 482, ISBN: 978-3-658-25050-8
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  Kurzfassung

  Der Beitrag analysiert eine TV-Debatte zur Bundestagswahl 2017 mit einem Mehrpersonenpodium unter Beteiligung der "kleinen" Parteien. Auf Basis von Echtzeit- und Umfragedaten formuliert der Beitrag nach eingehender Analyse fünf zentrale Befunde: 1) Je weiter politisch die Debattenteilnehmer auseinanderliegen, desto polarisierter und konfliktiver ist die Debatte. 2) Anhänger, die sich politisch einem Lager zurechnen bewerten auch den bzw. die Repräsentanten dieses Lagers deutlich besser. 3) Debattenteilnehmer anderer politischer Lager werden systematisch schlechter bewertet. 4) Ein besonderer Bias durch die Moderation liegt für die untersuchte Debatte nicht vor. 5) Die direkte Bedeutung von TV-Debatten für die Wahlentscheidung ist begrenzt.
• Benjamin Thiemann, Linus Feiten, Pascal Raiola, Bernd Becker, Matthias Sauer
  On Integrating Lightweight Encryption in Reconfigurable Scan Networks
  2019 IEEE European Test Symposium
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  Kurzfassung

  The applicability of the method is demonstrated by an FPGA-based implementation. We report on the performance of the developed instrument wrapper, which is empirically shown to have only a small impact on the workflow in terms of hardware overhead, operational costs and test time overhead.
• Sebastian Weydner-Volkmann, Linus Feiten
  Vertrauensstiftende Videoüberwachung?
  2019 digma: Zeitschrift für Datenrecht und Informationssicherheit, Band: 19, Nummer: 4, Seiten: 218 - 221

2018

 nach oben zur Jahresübersicht

• Linus Feiten, Karsten Scheibler, Bernd Becker, Matthias Sauer
  Using different LUT paths to increase area efficiency of RO-PUFs on Altera FPGAs
  2018 TRUDEVICE Workshop, Dresden
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  Kurzfassung

  Furthermore, the number of PUF response bits can be increased even further without extra hardware or software if a certain degree of correlations among the response bits is accepted. The degree of correlations is proportional to the growth of response bits, so a design decision can be made. To make this decision, a metric to quantify the degree of correlations is needed, which has so far been mostly neglected in the analyses of PUF implementations.
• Uwe Wagschal, Thomas Metz, Thomas Waldvogel, Bernd Becker, Linus Feiten, Samuel Weishaupt
  Online real-time-response measurement in real life settings: the Debat-O-Meter
  2018 Cologne 20th General Online Research Conference (GOR)
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  Kurzfassung

  Political debates have attracted substantial public and academic attention due to their prominent role in election campaigns. Reaching a tremendous number of potential voters, TV debates concentrate the electoral contest into a one-evening format that covers all major topics and main contenders. As "miniature campaigns" they reach many undecided and serve as (often the only) source of direct campaign information for voters less sophisticated or attentive to politics. In recent years Real Time Response Measurement gained international importance in political communication research.

2017

 nach oben zur Jahresübersicht

• Uwe Wagschal, Bernd Becker, Thomas Metz, Thomas Waldvogel, Linus Feiten
  Real-time evaluation of political debates at home and abroad with the Debat-O-Meter
  2017 Berlin 19th General Online Research Conference (GOR)
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  Kurzfassung

  Due to their role in election campaigns, televised debates between political candidates (“TV-Duelle”) have attracted substantial scholarly attention. A large body of work has used physical feedback devices to measure viewers’ reactions to a debate in real-time. However, this approach is limited to lab-based settings with potential negative ramifications for e.g. external validity. Therefore, a method freeing researchers from the need to use physical devices is called for.
• Matthias Sauer, Pascal Raiola, Linus Feiten, Bernd Becker, Ulrich Rührmair, Ilia Polian
  Sensitized Path PUF: A Lightweight Embedded Physical Unclonable Function
  2017 Conf. on Design, Automation and Test in Europe
• Uwe Wagschal, Thomas Waldvogel, Thomas Metz, Bernd Becker, Linus Feiten, Samuel Weishaupt, Kamaljeet Singh
  Das TV-Duell und die Landtagswahl in Schleswig-Holstein: Das Debat-O-Meter als neues Instrument der politischen Kommunikationsforschung
  2017 Zeitschrift für Parlamentsfragen (ZParl), Band: 48. Jg., Nummer: 3, Seiten: 594 - 613
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  Kurzfassung

  Politische TV-Debatten sind das Großereignis in modernen Wahlkämpfen und verstärkt Gegenstand von politik- und kommunikationswissenschaftlichen Untersuchungen. Die bisherige Forschung verwendete physische Eingabegeräte, die die Forscher auf Laborsettings mit kleinen Fallzahlen und negativen Effekten auf die externe Validität der Messung festlegte. Der Beitrag präsentiert eine Studie zur Landtagswahl in Schleswig-Holstein 2017 mit dem Debat-O-Meter, eine neue internetbasierte Anwendung für Smartphones, Tablets und PCs, die die Analyse von Wahrnehmungen und Wirkungen von politischen TV-Debatten mit einer großen Anzahl an Teilnehmenden in natürlichen Rezeptionssituationen erlaubt. Es wird gezeigt, dass „Real-Time Response“-Messungen (RTR) mit einer großen Teilnehmerzahl von mehr als 850 durch neue Wege der Rekrutierung mithilfe von Medienpartnern außerhalb des Labors möglich sind. Die Analyse belegt, dass Herausforderer Daniel Günther (CDU) die Debatte für sich entscheiden konnte und identifiziert die Parteineigung, die RTR-Bewertung und die Kandidateneinschätzung in der Vorbefragung als erklärungskräftigste Variablen für den Debattensieg.
• Linus Feiten, Matthias Sauer, Bernd Becker
  Implementation of Delay-Based PUFs on Altera FPGAs
  In: Hardware Security and Trust: Design and Deployment of Integrated Circuits in a Threatened Environment
  2017, Springer International Publishing, Seiten: 211 - 235, ISBN: 978-3-319-44318-8
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  Kurzfassung

  This chapter focuses on the implementation of delay-based PUFs on Altera FPGAs. While there has been a manifold of publications on how to evaluate and refine PUFs, a thorough description of the required "handicrafts" enabling a novice to enter this exciting research field has so far been missing. The methods shared in this chapter are not just easily extractable from available standard documentation, but have been compiled by the authors over a long period of trials and consultations with the Altera user community. Designing a delay-based PUF on FPGAs requires fine-tuning which is often like diverting the automated design tools from their intended use. For example, the device-specific delays for the PUF response generation are generally gathered from circuitry looking redundant to the bitstream compiler. Therefore, the automatic reduction of such seemingly redundant circuitry must be prevented. The way the circuitry is placed and routed also has a major impact on delay characteristics, so it is necessary to customise this instead of letting the compiler do it automatically. The reader will be walked through all necessary steps by means of a running example enabling them to embark on further experiments on their own. Along the way, the architecture of Altera Cyclone FPGAs is explained and results from the authors' own experimental studies are shared.

2016

 nach oben zur Jahresübersicht

• Sebastian Volkmann, Linus Feiten, Christian Zimmermann, Sebastian Sester, Laura Wehle, Bernd Becker
  Digitale Tarnkappe: Anonymisierung in Videoaufnahmen
  2016 INFORMATIK 2016 Gesellschaft für Informatik (GI), Heinrich C. Mayr, Martin Pinzger, Band: P-252, Seiten: 413 - 426
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  Kurzfassung

  Videoüberwachung ist heute allgegenwärtig. Sie dient dazu, Delikte im Nachhinein aufzuklären, zur Echtzeit-Überwachung oder zur Abschreckung. Darüber hinaus gibt es aber auch wirtschaftliche Interessen für eine Videoüberwachung und automatische Erfassung von Personen - z.B. zur Erstellung von Kundenprofilen und somit zur Analyse von Kaufverhalten. Dem gegenüber stehen Rechtsansprüche sowie ethische und gesellschaftliche Grundnormen, etwa dass Menschen nicht unter Generalverdacht gestellt oder ohne Zustimmung aufgezeichnet werden dürfen. In dieser Arbeit wird ein technischer Lösungsansatz behandelt, der eine flexible Handhabung der Videoüberwachung erlaubt. Es werden in diesem Zusammenhang neben der technischen Umsetzung auch ökonomische, ethische und juristische Fragen betrachtet. Der Lösungsansatz besteht darin, Personen auf Videoaufnahmen durch ein kryptographisches Verfahren unkenntlich zu machen, noch bevor die Aufnahmen die Kamera-Elektronik verlassen. Nur mittels eines geheimen kryptographischen Schlüssels können einzelne Zeit- und Bildbereiche einer Aufnahme wieder deanonymisiert werden, wodurch rechtlichen wie ethischen Bedenken Rechnung getragen werden kann. In kommerziellen Szenarien erlaubt es diese digitale Tarnkappe, dass Kunden z.B. im Rahmen eines Prämien-Programms freiwillig auf Anonymisierung verzichten. Während in der Literatur der Informatik bereits seit längerem Technologien für solche System beschrieben werden, werden in dieser Arbeit Wege gezeigt, wie dessen Einbettung in die Gesellschaft wirklich realisiert werden könnte.
• Linus Feiten, Matthias Sauer, Bernd Becker
  On Metrics to Quantify the Inter-Device Uniqueness of PUFs
  2016 TRUDEVICE Workshop, Dresden
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  Kurzfassung

  presented in the literature. An important criterion is always the diversity of PUF responses for different devices, called inter-device uniqueness. A very popular uniqueness metric consists of calculating the pairwise hamming distance between the response bit-strings of all devices, assuming that all response bits are uncorrelated. Such correlations, however, should be regarded when a statement about inter-device uniqueness is made. We therefore propose a novel correlation metric to fulfil this requirement. Furthermore, we show that the hamming distance metric is actually redundant when at the same time the also popular bit-aliasing metric is applied.
• Thomas Metz, Uwe Wagschal, Thomas Waldvogel, Marko Bachl, Linus Feiten, Bernd Becker
  Das Debat-O-Meter: ein neues Instrument zur Analyse von TV-Duellen
  2016 ZSE Zeitschrift für Staats- und Europawissenschaften, Band: 14, Nummer: 1, Seiten: 124 - 149
• Linus Feiten, Sebastian Sester, Christian Zimmermann, Sebastian Volkmann, Laura Wehle, Bernd Becker
  Revocable Anonymisation in Video Surveillance: A "Digital Cloak of Invisibility"
  In: Technology and Intimacy: Choice or Coercion
  2016, Springer International Publishing, Seiten: 314 - 327, ISBN: 978-3-319-44804-6
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  Kurzfassung

  Video surveillance is an omnipresent phenomenon in today's metropolitan life. Mainly intended to solve crimes, to prevent them by realtime-monitoring or simply as a deterrent, video surveillance has also become interesting in economical contexts; e.g. to create customer profiles and analyse patterns of their shopping behaviour. The extensive use of video surveillance is challenged by legal claims and societal norms like not putting everybody under generalised suspicion or not recording people without their consent. In this work we propose a technological solution to balance the positive and negative effects of video surveillance. With automatic image recognition algorithms on the rise, we suggest to use that technology to not just automatically identify people but blacken their images. This blackening is done with a cryptographic procedure allowing to revoke it with an appropriate key. Many of the legal and ethical objections to video surveillance could thereby be accommodated. In commercial scenarios, the operator of a customer profiling program could offer enticements for voluntarily renouncing one's anonymity. Customers could e.g. wear a small infrared LED to signal their agreement to being tracked. After explaining the implementation details, this work outlines a multidisciplinary discussion incorporating an economic, ethical and legal viewpoint.
• Bernd Becker, Katrin Weber, Linus Feiten
  SMartphones In der LEhre (SMILE)
  In: Kreativ, Innovativ, Motivierend - Lehrkonzepte in der Praxis: Der Instructional Development Award (IDA) der Universität Freiburg
  2016, Universitäts Verlag Webler (UVW), Seiten: 117 - 133, ISBN: 3-946017-01-0
• Linus Feiten, Jonathan Oesterle, Tobias Martin, Matthias Sauer, Bernd Becker
  Systematic Frequency Biases in Ring Oscillator PUFs on FPGAs
  2016 IEEE Transactions on Multi-Scale Computing Systems (TMSCS), Band: PP, Nummer: 99
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  Kurzfassung

  Physically unclonable functions (PUFs) are an emerging primitive in hardware security, enabling the identification of computer-chips. A promising type particularly for FPGA implementations is the Ring Oscillator (RO) PUF, where signal delays – stemming from uncontrollable variations in the manufacturing process – are used as device-specific characteristics. Based on experimental results gathered with 38 identical Altera FPGAs, we show the existence of nondevice- specific i.e. systemic RO frequency biases, traced back to (1) the internal routing within the RO’s look-up tables, (2) the RO locations on the FPGAs, or (3) the non-PUF payload activity. As these biases are the same for all devices, the result is poor inter-device uniqueness and unreliable signatures under changing payloads. After characterising these biases with a newly developed set of metrics, we suggest a method to overcome them: Using only a small sample of devices, the average bias over all devices for each RO is predicted and the relative differences caused by systemic biases are nullified. We demonstrate the viability of this method by determining the sufficient random sample sizes and showing that the inter-device uniqueness is drastically increased and the PUF signatures become reliable even under changing payload activities.
• Matthias Sauer, Linus Feiten, Bernd Becker, Ulrich Rührmair, Ilia Polian
  Utilizing Intrinsic Delay Variability in Complex Digital Circuits for Defining PUF Behavior
  2016 TRUDEVICE Workshop, Dresden

2015

 nach oben zur Jahresübersicht

• Linus Feiten, Tobias Martin, Matthias Sauer, Bernd Becker
  Improving RO-PUF Quality on FPGAs by Incorporating Design-Dependent Frequency Biases
  2015 IEEE European Test Symposium
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  Kurzfassung

  the mean frequency of each RO - derived using only a small training set of devices - from the sampled frequencies overcomes this disadvantage; i.e. the uniqueness is increased drastically while maintaining reliability.
• Linus Feiten, Tobias Martin, Matthias Sauer, Bernd Becker
  Analysis and utilisation of deviations in RO-PUFs under altered FPGA designs
  2015 TRUDEVICE Workshop, Grenoble
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  Kurzfassung

  Here, we are sharing our experiences from analyses on 70 FPGAs about how ROs implemented on Altera Cyclone IV FPGAs are affected in non-uniform ways depending on the non-PUF circuitry of the design. As specific ROs are affected towards faster or slower frequencies on all devices, this leads to bad inter-device uniqueness. We suggest that subtracting the mean frequency - derived with a training set of devices - from the sampled frequencies per RO on all devices will overcome this disadvantage.
• Linus Feiten, Matthias Sauer
  Extracting the RC4 secret key of the Open Smart Grid Protocol (OSGP)
  2015 Industrial Control System Security (ICSS) Workshop
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  Kurzfassung

  The Open Smart Grid Protocol (OSGP) is a widely used industry standard for exchanging sensitive data between devices inside of smart grids. For message confidentiality, OSGP implements a customised form of the RC4 stream cipher. In this work, we show how already known weaknesses of RC4 can be exploited to successfully attack the OSGP implementation as well. The attack modification is able to effectively derive the secret OSGP encryption and decryption key, given that an attacker can accumulate the cipher streams of approximately 90,000 messages. The possession of this key allows the attacker to decrypt all data intercepted on the OSGP smart grid and thereby obtain privacy critical information of its participants.
• Linus Feiten, Matthias Sauer, Tobias Schubert, Victor Tomashevich, Ilia Polian, Bernd Becker
  Formal Vulnerability Analysis of Security Components
  2015 IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems (TCAD), Band: 34, Nummer: 8, Seiten: 1358 - 1369
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  Kurzfassung

  Vulnerability to malicious fault attacks is an emerging concern for hardware circuits that are employed in mobile and embedded systems and process sensitive data. We describe a new methodology to assess the vulnerability of a circuit to such attacks, taking into account built-in protection mechanisms. Our method is based on accurate modeling of fault effects and detection status expressed by Boolean satisfiability (SAT) formulas. Vulnerability is quantified based on the number of solutions of these formulas, which are determined by an efficient #SAT solver. We demonstrate the applicability of this method for design space exploration of a pseudo random number generator and for calculating the attack success rate in a multiplier circuit protected by robust error-detecting codes.

2014

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• Linus Feiten, Andreas Spilla, Matthias Sauer, Tobias Schubert, Bernd Becker
  Implementation and Analysis of Ring Oscillator PUFs on 60 nm Altera Cyclone FPGAs
  2014 Information Security Journal: A Global Perspective, Band: 22, Nummer: 5-6, Seiten: 265 - 273
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  Kurzfassung

  Ring Oscillator (RO) physically unclonable functions (PUFs) on field programmable gate arrays (FPGAs) have drawn much attention in recent years. Making each FPGA uniquely identifiable, they allow for protection of intellectual property (IP) or generation of secret encryption keys. Their implementation has been widely discussed, but most experiments have been conducted on Xilinx platforms. In this paper, we report the statistical results from an analysis spanning 20 Cyclone IV FPGAs with 60 nm technology. We parameterize the RO length, placement, ambient temperature, and non-PUF switching activity and discuss the observed effects on PUF quality.

2013

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• Linus Feiten, Katrin Weber, Bernd Becker
  SMILE: Smartphones in der Lehre – ein Rück- und Überblick
  2013 INFORMATIK 2013 Gesellschaft für Informatik (GI), Matthias Horbach, Band: P-220, Seiten: 255 - 269
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  Kurzfassung

  Bei SMILE handelt es sich um ein Projekt, das im Wintersemester 2010 gestartet wurde. Sein fortlaufendes Ziel ist die Erforschung von Möglichkeiten, die universitäre Lehre - insbesondere Vorlesungen mit über hundert Studierenden - durch den Einsatz von IT zu bereichern. Hierfür wurden Apps für Studierende und Dozierenden entwickelt, die auf allen gängigen Geräten laufen. Die konzeptionelle Planung liegt bei einem interdisziplinären Team aus Informatikern und Instructional Designern; für die Implementierung wird eng mit einem studentischen Entwicklerteam zusammen gearbeitet. Zwei Preisauszeichnungen zeigen die positive Resonanz, die SMILE bisher hervor gerufen hat. Im Sommersemester 2013 wird SMILE zum vierten Mal in einer größeren Vorlesung eingesetzt. In diesem Workshop-Paper beschreiben wir den bisherigen Verlauf des Projekts und die Kernfunktionalitäten der Software.
• Linus Feiten, Andreas Spilla, Matthias Sauer, Tobias Schubert, Bernd Becker
  Analysis of Ring Oscillator PUFs on 60nm FPGAs
  2013 TRUDEVICE Workshop, Avignon
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  Kurzfassung

  The implementation of RO PUFs on FPGAs has been widely discussed but most experiments have been conducted on Xilinx FPGAs. In this paper we are reporting statistical results from an analysis spanning 20 equivalent Altera FPGAs. The presented results include the PUF quality's dependency on different parameters like RO length and placement on the FPGA. We identify the optimal RO length of 16 Logic Elements (LE) and show some specific placement cases for which the otherwise very good PUF quality decreases drastically.
• Linus Feiten, Matthias Sauer, Tobias Schubert, Alexander Czutro, Victor Tomashevich, Eberhard Böhl, Ilia Polian, Bernd Becker
  #SAT for Vulnerability Analysis of Security Components
  2013 (Workshop-Paper, Informal Proceedings) IEEE European Test Symposium
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  Kurzfassung

  Vulnerability to malicious fault attacks is an emerging concern for hardware circuits that process sensitive data.We describe a new methodology to assess the vulnerability to such attacks, taking into account built-in protection mechanisms. Our method is based on accurate modeling of fault effects and their detection status expressed as Boolean satisfiability (SAT) formulae. Vulnerability is quantified based on the number of solutions of such formulae, which are computed by an eficient #SAT solver. We demonstrate the applicability of this method by analyzing a sequential pseudo random number generator and a combinatorial multiplier circuit both protected by robust error-detecting codes.
• Renatus Derbidge, Linus Feiten, Oliver Conradt, Peter Heusser, Stefan Baumgartner
  Assessment of Shape Changes of Mistletoe Berries: A New Software Approach to Automatize the Parameterization of Path Curve Shaped Contours
  2013 Plos One, Band: 8, Nummer: 4
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  Kurzfassung

  Photographs of mistletoe (Viscum album L.) berries taken by a permanently fixed camera during their development in autumn were subjected to an outline shape analysis by fitting path curves using a mathematical algorithm from projective geometry. During growth and maturation processes the shape of mistletoe berries can be described by a set of such path curves, making it possible to extract changes of shape using one parameter called Lambda. Lambda describes the outline shape of a path curve. Here we present methods and software to capture and measure these changes of form over time. The present paper describes the software used to automatize a number of tasks including contour recognition, optimization of fitting the contour via hill-climbing, derivation of the path curves, computation of Lambda and blinding the pictures for the operator. The validity of the program is demonstrated by results from three independent measurements showing circadian rhythm in mistletoe berries. The program is available as open source and will be applied in a project to analyze the chronobiology of shape in mistletoe berries and the buds of their host trees.

2012

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• Linus Feiten, Matthias Sauer, Tobias Schubert, Alexander Czutro, Eberhard Böhl, Ilia Polian, Bernd Becker
  #SAT-Based Vulnerability Analysis of Security Components -- A Case Study
  2012 IEEE International Symposium on Defect and Fault Tolerance (DFT), Seiten: 49 - 54
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  Kurzfassung

  In this paper we describe a new approach to assess a circuit's vulnerability to fault attacks. This is achieved through analysis of the circuit's design specification, making use of modern SAT solving techniques. For each injectable fault, a corresponding SAT instance is generated. Every satisfying solution for such an instance is equivalent to a circuit state and an input assignment for which the fault affcts the circuit's outputs such that the error is not detected by the embedded fault detection. The number of solutions is precisely calculated by a #SAT solver and can be translated into an exact vulnerability measure. We demonstrate the applicability of this method for design space exploration by giving detailed results for various implementations of a deterministic random bit generator.
• Linus Feiten, Manuel Bührer, Sebastian Sester, Bernd Becker
  SMILE - SMARTPHONES IN LECTURES - Initiating a Smartphone-based Audience Response System as a Student Project
  2012 4th International Conference on Computer Supported Education (CSEDU), Seiten: 288 - 293
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  Kurzfassung

  Final results of the evaluation will be subject to a later publication later. Here we are sharing first tendenciesalready observable and details of the conception and the ongoing development phases.
• Celia Kändler, Linus Feiten, Katrin Weber, Michael Wiedmann, Manuel Bührer, Sebastian Sester, Bernd Becker
  university learning environment: a classroom response system
  2012 International Conference of the Learning Sciences (ICLS), International Society of the Learning Sciences, Band: 2, Seiten: 515 - 516
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  Kurzfassung

  We describe and evaluate a tool using smartphones in a university learning environment. Mass lectures often lack in interactivity. Due to missing feedback, the lecture’s content may not be adapted to the students' understanding. The tool consists of two modules, a comprehension level visualization and multiple choice questions, that are hypothesized to increase interactivity and adaptation to students' understanding. We report data from a formative evaluation of the tool's first implementation in a university lecture.