More Structural Characterizations of Some Subregular Language Families by Biautomata

We study structural restrictions on biautomata such as, e.g., acyclicity, permutation-freeness, strongly permutation-freeness, and orderability, to mention a few. We compare the obtained language families with those induced by deterministic finite automata with the same property. In some cases, it is shown that there is no difference in characterization between deterministic finite automata and biautomata as for the permutation-freeness, but there are also other cases, where it makes a big difference whether one considers deterministic finite automata or biautomata. This is, for instance, the case when comparing strongly permutation-freeness, which results in the family of definite language for deterministic finite automata, while biautomata induce the family of finite and co-finite languages. The obtained results nicely fall into the known landscape on classical language families.Comment: In Proceedings AFL 2014, arXiv:1405.527

Synthesis of Diarylaminoacridinium Photocatalysts by Halogen-Metal Exchange Combined with Directed ortho Metalations

Photostability is an essential design aspect for the overall performance of photocatalysts, particularly as groups introduced to adjust redox properties often constitute sites of potential reactivity. Herein, we describe a modular and flexible synthetic approach to incorporate diarylamino moieties with increased photostability that allow to efficiently tune the redox behavior of a new generation of organic acridinium photocatalysts. A series of cross-coupling reactions gave access to precursors for halogen metal exchange reactions combined with directed ortho-metalations to provide reagents that allow the formation of acridinium salts with adjustable redox properties and enhanced photostability in good yields

A General Protocol for Robust Sonogashira Reactions in Micellar Medium

A robust and general protocol for a sustainable copper‐free Sonogashira cross coupling under micellar aqueous reaction conditions with high turnover was developed. By using the commercially available catalyst CataCXium A Pd G3 and THF as co‐solvent, various alkyne substrates were efficiently cross‐coupled with a broad range of aryl halides, providing improved yields and low catalyst loadings. The reaction parameters were optimized to render the process operationally simple, robust and scalable. The method gives access to alkynylated arenes, heterocyclic compounds, and monofunctionalized products from dihalogenated substrates with an improved selectivity achieved by the micellar aqueous reaction conditions

Das Benfordsche Gesetz und seine Anwendbarkeit bei der digitalen Prüfung von Fahrtenbüchern

Das Vertrauen in die Aussagekraft der Abschlussprüfungen wurde in den letzten Jahren durch eine Vielzahl von Bilanzskandalen erschüttert. Um Fälschungen und Missbrauch leichter und effizienter bekämpfen zu können und den technischen Entwicklungen Rechnung zu tragen, wird bereits seit längerem in der Betriebsprüfung der Finanzämter auf mathematisch-statistische Methoden wie bspw. insbesondere die sogenannte Benford-Analyse oder den Chi-Quadrat-Anpassungstest zurückgegriffen. Mit Hilfe dieser Auswertungen werden Ziffern auf bestimmte Muster untersucht. In dem Arbeitsbericht wird zunächst die Zulässigkeit dieser mathematisch-statistischen Methoden in der digitalen Betriebsprüfung erläutert und neben den generellen Vorschriften zur Führung von Fahrtenbüchern wird der Anreiz zur Fälschung von Fahrtenbüchern verdeutlicht. Daran anschließend setzt sich diese Arbeit grundlegend mit dem Einsatz des Chi-Quadrat-Anpassungstests sowie dem Benford’s Law auseinander. Auch die Anwendung dieser Methoden wird anhand des Urteils des FG Münster vom 7.12.2005 dargestellt und einer kritischen Würdigung unterzogen. Darauf aufbauend werden mögliche Ansätze für empirische Untersuchungen beschrieben. Dabei werden neben grundlegenden Vorüberlegungen auch erwägbare Ansätze zur Interpretation der Ergebnisse vermittelt. Der Bericht schließt mit einer kritischen Zusammenfassung und gibt einen Ausblick über denkbare künftige empirische Untersuchungen

Practical private database queries based on a quantum key distribution protocol

Private queries allow a user Alice to learn an element of a database held by a provider Bob without revealing which element she was interested in, while limiting her information about the other elements. We propose to implement private queries based on a quantum key distribution protocol, with changes only in the classical post-processing of the key. This approach makes our scheme both easy to implement and loss-tolerant. While unconditionally secure private queries are known to be impossible, we argue that an interesting degree of security can be achieved, relying on fundamental physical principles instead of unverifiable security assumptions in order to protect both user and database. We think that there is scope for such practical private queries to become another remarkable application of quantum information in the footsteps of quantum key distribution.Comment: 7 pages, 2 figures, new and improved version, clarified claims, expanded security discussio

The Magic Number Problem for Subregular Language Families

We investigate the magic number problem, that is, the question whether there exists a minimal n-state nondeterministic finite automaton (NFA) whose equivalent minimal deterministic finite automaton (DFA) has alpha states, for all n and alpha satisfying n less or equal to alpha less or equal to exp(2,n). A number alpha not satisfying this condition is called a magic number (for n). It was shown in [11] that no magic numbers exist for general regular languages, while in [5] trivial and non-trivial magic numbers for unary regular languages were identified. We obtain similar results for automata accepting subregular languages like, for example, combinational languages, star-free, prefix-, suffix-, and infix-closed languages, and prefix-, suffix-, and infix-free languages, showing that there are only trivial magic numbers, when they exist. For finite languages we obtain some partial results showing that certain numbers are non-magic.Comment: In Proceedings DCFS 2010, arXiv:1008.127

A dense network of cosmic-ray neutron sensors for soil moisture observation in a highly instrumented pre-Alpine headwater catchment in Germany

Monitoring soil moisture is still a challenge: it varies strongly in space and time and at various scales while conventional sensors typically suffer from small spatial support. With a sensor footprint up to several hectares, cosmic-ray neutron sensing (CRNS) is a modern technology to address that challenge. So far, the CRNS method has typically been applied with single sensors or in sparse national-scale networks. This study presents, for the first time, a dense network of 24 CRNS stations that covered, from May to July 2019, an area of just 1 km2: the pre-Alpine Rott headwater catchment in Southern Germany, which is characterized by strong soil moisture gradients in a heterogeneous landscape with forests and grasslands. With substantially overlapping sensor footprints, this network was designed to study root-zone soil moisture dynamics at the catchment scale. The observations of the dense CRNS network were complemented by extensive measurements that allow users to study soil moisture variability at various spatial scales: roving (mobile) CRNS units, remotely sensed thermal images from unmanned areal systems (UASs), permanent and temporary wireless sensor networks, profile probes, and comprehensive manual soil sampling. Since neutron counts are also affected by hydrogen pools other than soil moisture, vegetation biomass was monitored in forest and grassland patches, as well as meteorological variables; discharge and groundwater tables were recorded to support hydrological modeling experiments. As a result, we provide a unique and comprehensive data set to several research communities: to those who investigate the retrieval of soil moisture from cosmic-ray neutron sensing, to those who study the variability of soil moisture at different spatiotemporal scales, and to those who intend to better understand the role of root-zone soil moisture dynamics in the context of catchment and groundwater hydrology, as well as land–atmosphere exchange processes. The data set is available through the EUDAT Collaborative Data Infrastructure and is split into two subsets: https://doi.org/10.23728/b2share.282675586fb94f44ab2fd09da0856883 (Fersch et al., 2020a) and https://doi.org/10.23728/b2share.bd89f066c26a4507ad654e994153358b (Fersch et al., 2020b)

Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector

A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements