University of Applied Sciences Emden Leer
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509 research outputs found
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Clostridioides difficile from Fecally Contaminated Environmental Sources: Resistance and Genetic Relatedness from a Molecular Epidemiological Perspective
No full textClostridioides difficile is the most important pathogen causing antimicrobial-associated diarrhea and has recently been recognized as a cause of community-associated C. difficile infection (CA-CDI). This study aimed to characterize virulence factors, antimicrobial resistance (AMR), ribotype (RT) distribution and genetic relationship of C. difficile isolates from diverse fecally contaminated environmental sources. C. difficile isolates were recovered from different environmental samples in Northern Germany. Antimicrobial susceptibility testing was determined by E-test or disk diffusion method. Toxin genes (tcdA and tcdB), genes coding for binary toxins (cdtAB) and ribotyping were determined by PCR. Furthermore, 166 isolates were subjected to whole genome sequencing (WGS) for core genome multi-locus sequence typing (cgMLST) and extraction of AMR and virulence-encoding genes. Eighty-nine percent (148/166) of isolates were toxigenic, and 51% (76/148) were positive for cdtAB. Eighteen isolates (11%) were non-toxigenic. Thirty distinct RTs were identified. The most common RTs were RT127, RT126, RT001, RT078, and RT014. MLST identified 32 different sequence types (ST). The dominant STs were ST11, followed by ST2, ST3, and ST109. All isolates were susceptible to vancomycin and metronidazole and displayed a variable rate of resistance to moxifloxacin (14%), clarithromycin (26%) and rifampicin (2%). AMR genes, such as gyrA/B, blaCDD-1/2, aph(3′)-llla-sat-4-ant(6)-la cassette, ermB, tet(M), tet(40), and tetA/B(P), conferring resistance toward fluoroquinolone, beta-lactam, aminoglycoside, macrolide and tetracycline antimicrobials, were found in 166, 137, 29, 32, 21, 72, 17, and 9 isolates, respectively. Eleven “hypervirulent” RT078 strains were detected, and several isolates belonged to RTs (i.e., RT127, RT126, RT023, RT017, RT001, RT014, RT020, and RT106) associated with CA-CDI, indicating possible transmission between humans and environmental sources pointing out to a zoonotic potential
On Perfect Linear Approximations and Differentials over Two-Round SPNs [Revision in ePrint Archive]
No full textRecent constructions of (tweakable) block ciphers with an embedded cryptographic backdoor relied on the existence of probability-one differentials or perfect (non-)linear approximations over a reduced-round version of the primitive. In this work, we study how the existence of probability-one differentials or perfect linear approximations over two rounds of a substitution-permutation network can be avoided by design. More precisely, we develop criteria on the s-box and the linear layer that guarantee the absence of probability-one differentials for all keys. We further present an algorithm that allows to efficiently exclude the existence of keys for which there exists a perfect linear approximation
Commutative Cryptanalysis Made Practical
No full textAbout 20 years ago, Wagner showed that most of the (then) known techniques used in the cryptanalysis of block ciphers were particular cases of what he called commutative diagram cryptanalysis. However, to the best of our knowledge, this general framework has not yet been leveraged to find concrete attacks.
In this paper, we focus on a particular case of this framework and develop commutative cryptanalysis, whereby an attacker targeting a primitive E constructs affine permutations A and B such that E ○ A = B ○ E with a high probability, possibly for some weak keys. We develop the tools needed for the practical use of this technique: first, we generalize differential uniformity into “A-uniformity” and differential trails into “commutative trails”, and second we investigate the commutative behaviour of S-box layers, matrix multiplications, and key additions.
Equipped with these new techniques, we find probability-one distinguishers using only two chosen plaintexts for large classes of weak keys in both a modified Midori and in Scream. For the same weak keys, we deduce high probability truncated differentials that can cover an arbitrary number of rounds, but which do not correspond to any high probability differential trails. Similarly, we show the existence of a trade-off in our variant of Midori whereby the probability of the commutative trail can be decreased in order to increase the weak key density. We also show some statistical patterns in the AES super S-box that have a much higher probability than the best differentials, and which hold for a class of weak keys of density about 2−4.5
Rethinking LoRa for the IoT: An InformationCentric Approach
No full textIn this article, we present LoRa-ICN, a new long-range communication system that provides a versatile data-oriented integration of battery-driven LoRa nodes into the Internet of Things (IoT). LoRa-ICN builds on two paradigms: information-centric networking (ICN), which enables more direct, data-oriented communication between Internet systems and the low-power wireless domain, and 802.15.4 DSME, which is an IoT MAC layer that facilitates reliable LoRa transmissions. While the combination of LoRa and DSME is generally better suited for bi-directional end-to-end communication, it still incurs considerable long and variable transmission latencies, and challenges the network layer transition between the power-constrained wireless domain and the Internet. Our design and implementation on actual off-the-shelf IoT hardware includes extensions to ICN that enable delay-tolerant data retrieval between LoRa nodes and an application on the Internet. An experimental comparison between default ICN mechanisms and our extensions shows that LoRa-ICN is able to achieve a high data delivery rate, while dealing with the higher latencies explicitly, thus providing a viable option for re-imaging LoRa networks with a data-oriented, Internet-friendly approach
Design and Evaluation of Voice User Interfaces: What Should One Consider?
No full textVoice user interfaces (VUI) come in various forms of software or hardware, are controlled by voice, and can help the user in their daily life. Despite VUIs being readily available on smartphones, they have a low adoption rate. This can be attributed to challenges such as the misunderstanding of voice commands as well as privacy and data security concerns. Still, there are intensive VUI users, but they also raise concerns that may be independent of culture. Hence, we will discuss in our paper the various areas that should be considered when developing VUIs to increase user acceptance and foster a positive user experience (UX). We propose exploring the context of use and UX aspects to understand users’ needs while using VUIs. All of our suggestions can help VUI developers to design better VUIs
Reconstruction and Validation of the UX Factor Trust for the User Experience Questionnaire Plus (UEQ+)
No full textAs digital technologies advance, user experience (UX) has become crucial for software and services success. The User Experience Questionnaire Plus (UEQ+) is a flexible tool used to evaluate UX through questionnaires tailored to specific problems, yet a critical factor often overlooked is Trust. Trust, understood as a user’s belief in a software’s ability to function consistently, securely, and with respect for user data privacy, is especially pivotal in areas like financial services, health informatics, and e-commerce platforms. This paper focuses on
the construction and validation of Trust as a new factor in the UEQ+. During the construction phase, an initial collection of potential items was assembled for the trust factor. A subsequent study involving 405 participants facilitated the reduction of these items to four, a task accomplished via factor analysis. The proceeding stages involved two additional validation phases, enlisting a total of 897 participants, wherein the selected items were subject to validation. The culmination of this process resulted in a newly validated factor, Trust, which is constituted by the following items: insecure-secure, untrustworthy-trustworthy, unreliable-reliable, and non-transparent-transparent
Environmentally friendly solar energy: potential of utilizing field margins in rural areas for photovoltaic systems in combination with wildflower strips
No full textThis study assesses the economic potential of using field margins and wildflower strips in rural northwest Lower Saxony, Germany, for eco-friendly solar energy generation. Field margins, located at the edges of farmland, serve as buffers between crops and surrounding ecosystems and can promote biodiversity by using as wildflower strips. By integrating photovoltaic (PV) systems within these field margins, the study aims to investigate clean electricity production while preserving ecological balance. To estimate the potential of grid-connected field margin PV (FMPV), the paper considers regulatory, technical, and economic factors. Using geographic data, suitable areas are identified. The study assesses regulatory influence on FMPV operations and evaluates grid connection points' availability for economic analysis. Results show that 19,378 km of field margins are potentially suitable for grid-connected FMPV, implying an electricity generation potential of 23.6 TWh/a. However, compatible margins constitute just 15.5 % of existing field margins. The combination of wildflower strips and grid-connected FMPV provides an innovative energy approach in rural areas, however, this study highlights high grid connection costs. Offgrid photovoltaic systems seem more practical. Prioritizing off-grid systems for on-site electricity utilization and exploring affordable alternatives are essential for enhancing the economic viability of FMPV systems in rural areas
Experimente
No full textWie beim Problem mit der Fehler- und Lernkultur schon beschrieben, hängt dieses sehr nah mit dem nächsten Themenfeld rund um Experimente zusammen. Dieses Kapitel vertieft die Problematik, dass Menschen – egal ob als einzelne Individuen oder in einer Gruppe als Team – in Organisationen bzw. in ihrem Umfeld Angst davor haben, neue Dinge auszuprobieren. Der Begriff Experiment deutet bereits daraufhin, dass es noch keinen klaren Weg und kein vorhersagbares Ergebnis gibt und das Auszuprobierende schiefgehen kann
Zusammenfassung und Empfehlungen für die Praxis
No full textDieses essential beschreibt, welche Probleme beim Zusammenspiel agiler Arbeitsweisen und Kultur entstehen. Zunächst wurden hierzu die theoretischen Grundlagen zu Agilität und Kultur zusammengefasst. Wir haben die Begriffe Agilität, Agile Werte und Agile Organisation definiert, um ein gemeinsames Verständnis für die Konzepte zu schaffen. Daraufhin wurde das Konzept der Kultur anhand gängiger Modelle erläutert. Darauf aufbauend konnte der Zusammenhang zwischen technischer Agilität (doing agile) und kultureller Agilität (being agile) diskutiert werden
