Characterizations of recognizable picture series

AbstractThe theory of two-dimensional languages as a generalization of formal string languages was motivated by problems arising from image processing and pattern recognition, and also concerns models of parallel computing. Here we investigate power series on pictures. These are functions that map pictures to elements of a semiring and provide an extension of two-dimensional languages to a quantitative setting. We assign weights to different devices, ranging from picture automata to tiling systems. We will prove that, for commutative semirings, the behaviours of weighted picture automata are precisely alphabetic projections of series defined in terms of rational operations, and also coincide with the families of series characterized by weighted tiling or weighted domino systems

Stabilizers of Subspaces under Similitudes of the Klein Quadric, and Automorphisms of Heisenberg Algebras

We determine the groups of automorphisms and their orbits for nilpotent Lie algebras of class 2 and small dimension, over arbitrary fields (including the characteristic 2 case)

L-band Digital Aeronautical Communications System (LDACS) draft-maeurer-raw-ldacs-06

This document provides an overview of the architecture of the L-band Digital Aeronautical Communications System (LDACS), which provides a secure, scalable and spectrum efficient terrestrial data link for civil aviation. LDACS is a scheduled, reliable multi-application cellular broadband system with support for IPv6. LDACS shall provide a data link for IP network-based aircraft guidance. High reliability and availability for IP connectivity over LDACS are therefore essential

L-band Digital Aeronautical Communications System (LDACS) draft-maeurer-raw-ldacs-04

This document provides an overview of the architecture of the L-band Digital Aeronautical Communications System (LDACS), which provides a secure, scalable and spectrum efficient terrestrial data link for civil aviation. LDACS is a scheduled, reliable multi-application cellular broadband system with support for IPv6. LDACS shall provide a data link for IP network-based aircraft guidance. High reliability and availability for IP connectivity over LDACS are therefore essential

L-band Digital Aeronautical Communications System (LDACS) draft-ietf-raw-ldacs-03

This document provides an overview of the architecture of the L-band Digital Aeronautical Communications System (LDACS), which provides a secure, scalable and spectrum efficient terrestrial data link for civil aviation. LDACS is a scheduled, reliable multi-application cellular broadband system with support for IPv6. LDACS shall provide a data link for IP network-based aircraft guidance. High reliability and availability for IP connectivity over LDACS are therefore essential

Rational Decision Support with a Natural Language Dialogue System

In the past decades, technological advance has led to a revival of natural language dia- logue systems (or conversational agents). Now, conversational agents are used for profes- sional purposes such as customer support, marketing, e-learning, and tutoring purposes, just to mention a few. They also have found their way into everyday life, e.g. as speech- based personal assistants on mobile devices or as freely available text-based information retrieval systems in the web. However, there are still many unexplored application areas for conversational agents. Personal coaching, for example, is a promising field. Coaching has been successfully applied across many areas, for example in human resource devel- opment, team-building, and improvement of various individual skills such as leadership, communication or sales, and to support humans with rational decision-making. Never- theless, personal coaching by a human coach or counsellor is very expensive and therefore only available to a limited circle of individuals in organizations. So far, conversational agents have not been extensively used for personal coaching purposes. This work intends to explore the potential of conversational agents for simulated hu- man coaching or consulting. Therefore, we have developed VPINO, a text-based dialogue system, intended for holding structured coaching conversations in German language. This work provides a detailed description of VPINO. A general maxim of many modern coach- ing approaches is to regard the client as the expert for the relevant problem, rather than seeing the coach as the expert for the client’s problem. VPINO aims to open up a new perspective and help the “expert” develop his/her own solution. Instead of giving ad- vice or pushing the client into any certain direction, VPINO uses the technique of Socratic questioning, i.e. targeted questions to support clients to reflect on their goal accomplish- ment process. VPINO is an expert on structuring the user’s implicit knowledge and merely assists the user like a human coach. The intelligence or value of our dialogue system is not in its ability in detailed understanding what the user says and will therefore not pro- vide answers to particular questions. The key is that, nevertheless, VPINO understands yet enough to keep control over the conversation, in a way that will not be noticed by the user. To do so, the system determines the dialogue act of each user utterance, i.e. the function of that utterance for the conversation. A suitable response is selected from a set of preformu- lated utterances, based on a model of potential dialogue act sequences. VPINO has been developed for application in the particular scenarios of (1) training transfer coaching for communication skills and (2) rational decision support. The effectiveness and usefulness of VPINO in both scenarios are evaluated in a series of user studies. For the scenario of training transfer coaching, we conducted a field experimental study that evaluates the effectiveness of coaching, right after participants received an online com- munication training. Training transfer, the application of newly acquired skills in everyday work, requires a maximum of support and reflection. Our results suggest that a computer- based coaching with VPINO can effectively provide this support and improve the partici- pants communication skills. Moreover, we explored the influence of the user’s personality and behaviour when talking to the computer based coach. Whereas users that are more “open to new experience” particularly benefit from chat coaching with VPINO, more scep- tical and less cooperative users do not profit from using VPINO. For the scenario of rational decision coaching, VPINO was evaluated in a series of user studies. VPINO guides the users through a process of structured decision-making on a distinctly rational basis, in the spirit of Benjamin Franklin’s method “Pros and Cons”. Par- ticipants were free to talk about a decision problem of their own choice. Whereas VPINO could successfully help participants with rational problems, the conversation was less ef- fective with more emotionally stressful problems. However, participants with a generally less structured decision making approach particularly benefit from using VPINO. Partic- ipants that are generally more open to receiving support from an artificial coach evalu- ated the usefulness of the conversation higher than sceptical users. However, a high level of motivation and cooperativeness is required for fruitful conversation. In general, user expectations, behaviour, and willingness to cooperate have an influence on how users in- teract with the virtual coach. The use of chat language greatly varies between users in many dimensions, e.g. grammatical and syntactical correctness, style, length of answers, and politeness. This thesis shows that a natural language dialogue system can serve as a highly avail- able, cheap, low threshold solution to support a large target group, where a human per- sonal coach is not available

Secure Communications in Next Generation Digital Aeronautical Datalinks

As of 2022, Air Traffic Management (ATM) is gradually digitizing to automate and secure data transmission in civil aviation. New digital data links like the L-band Digital Aeronautical Communications System (LDACS) are being introduced for this purpose. LDACS is a cellular, ground-based digital communications system for flight guidance and safety. Unfortunately, LDACS and many other datalinks in civil aviation lack link layer security measures. This doctoral thesis proposes a cybersecurity architecture for LDACS, developing various security measures to protect user and control data. These include two new authentication and key establishment protocols, along with a novel approach to secure control data of resource-constrained wireless communication systems. Evaluations demonstrate a latency increase of 570 to 620 milliseconds when securely attaching an aircraft to an LDACS cell, along with a 5% to 10% security data overhead. Also, flight trials confirm that Ground-based Augmentation System (GBAS) can be securely transmitted via LDACS with over 99% availability. These security solutions enable future aeronautical applications like 4D-Trajectories, paving the way for a digitized and automated future of civil aviation

Eine ökonomische Analyse des Imkerei-Sektors in Deutschland

Die Studie gibt einen umfassenden Einblick in die aktuelle Situation des Imkereisektors und seine volkswirtschaftliche Bedeutung in Deutschland. Sie bezieht auch die eng mit dem Sektor verbundene Landwirtschaft mit ein, da diese beiden Sektoren sich wechselseitig beeinflussen und voneinander profitieren können. Dem Imkereisektor kommt speziell wegen der Honigbienenbestäubung im bestäubungsabhängigen Pflanzenbau eine hohe volkswirtschaftliche Bedeutung zu. Die Wertschöpfung der Honigbienenbestäubung im Nahrungspflanzenanbau wird mit maximal 1,6 Milliarden Euro auf das bis zu 13-fache der berechneten Wertschöpfung für Honig- und Wachs (ca. 0,12 Milliarden Euro) geschätzt. Anhand der Experteneinschätzungen und der räumlichen Analyse am Beispiel Baden-Württembergs liegt jedoch die Vermutung nahe, dass die derzeitige Dichte an Bienenvölkern vor allem in großstrukturierten Agrarlandschaften und in Sonderkulturanbauregionen keine ausreichende, flächendeckende Bestäubung sicherstellt. Um die aktuellen Herausforderungen zu identifizieren und mögliche Maßnahmen zu konzipieren, die eine (Bestäubungs-)Zusammenarbeit zwischen Imkern und Landwirten zukünftig fördern könnten, wurde die Expertise von Fachleuten aus beiden Sektoren im Rahmen von Leitfadeninterviews, einer schriftlichen Befragung und einem Experten-Workshop zusammengetragen. Aufgrund der dabei gewonnen Erkenntnisse wird empfohlen (1) das Thema Insektenbestäubung verstärkt in der Aus- und Fortbildung und Fachberatung zu berücksichtigen, (2) mehr praxisbezogene Forschung zum Thema Bestäubung durchzuführen und dabei offene Fragen zur Auswirkung von Pflanzenschutzmitteln auf Honigbienen und andere Bestäuberinsekten zu beantworten, (3) private und öffentliche Veranstaltungen, etwa Messen, Fachvorträge, Workshops, etc. für den Wissenstransfer zu nutzen, (4) private (Landwirt und Imker) und öffentliche Zusammenschlüsse (z.B.: Imker, Landwirte, Agrar- und Veterinärverwaltung) zu formen, (5) die Standorte von Bienenständen mit ihren jeweiligen Ansprechpartnern in einer zentralen Auskunftsplattform publik zu machen, sodass Landwirte „bienenrelevanten Tätigkeiten“ (z.B. der Einsatz von Pflanzenschutzmitteln) besser mit den betroffenen Imkern abstimmen können, (6) eine ausreichende finanzielle Förderung von Agrarumweltmaßnahmen und bienenfreundlichen Pflanzenschutztechniken zu gewährleisten, und (7) einen Bürokratieabbau in der Agrarverwaltung anzustreben. Ergänzend zeigt die Studie einen Datenmangel in verschiedenen Bereichen auf, welcher die ökonomische Analyse im Imkereisektor im Vergleich zu anderen Betriebszweigen der Tierhaltung erschwert

Regulation of mammalian Target Of Rapamycin (mTOR) signaling by “Protein Associated with Myc” (PAM)

Das “Protein Associated with Myc” spielt in den verschiedenen physiologischen Vorgängen eine Rolle. Dazu zählen Prozesse der Synaptogenese und Schmerzverarbeitung ebenso wie eine Regulation des Pteridin- und cAMP-Stoffwechsels. Auf welche Weise PAM die unterschiedlichen Effekte vermittelt, ist bislang nur in Ansätzen verstanden. Um die Wirkmechanismen von PAM aufzuklären, wurden in dieser Arbeit seine biochemischen Funktionen untersucht. Die These, dass PAM als E3 Ubiquitinligase aktiv ist, konnte in vitro mittels biochemischer Versuche zweifelsfrei bestätigt werden. Sowohl das nativ aufgereinigte, humane PAM, als auch der heterolog expremierte C-Terminale Bereich (C-PAM), der die katalytisch aktive RING Finger Domäne enthält, wiesen die Fähigkeit zur Ubiquitinkettenbildung und Autoubiquitinierung auf. Bei der Identifikation eines möglichen Zielproteins rückte das Protein TSC2 und der damit verbundene TSC2 / mTOR Signalweg in den Fokus. Für das gewählte Modell-System HeLa Zellen ließ sich eine Interaktion von PAM und TSC2 durch Ko-Immunopräzipitationen und Immunzytochemie nachweisen. Es konnte erstmalig gezeigt werden, dass das vollständige, native PAM, nicht aber die isolierte RING Finger Domäne, TSC2 polyubiquitinieren und zum proteasomalen Abbau markieren kann. TSC2 ist ein negativer Regulator der mTOR Kinaseaktivität, in dem es den stimulatorischen Einfluss von Rheb auf mTOR inhibiert. PAM wird in HeLa Zellen durch das Phospholipid Sphingosin-1-Phosphat (S1P) aktiviert. Nach S1P Behandlung der Zellen war eine Phosphorylierung der Proteinkinase mTOR nachweisbar. Diese ging mit einer Aktivierung der Kinaseaktivität einher, wie die rapamycinsensitive Phosphorylierung der mTOR Zielproteine p70S6K und 4E-BP1 zeigte. Durch Gabe von Rezeptor-Agonisten/-Antagonisten konnte eine Beteiligung des S1P1 und S1P2 Rezeptors ausgeschlossen werden. Der zunächst vermutete Mechanismus eines S1P induzierten, PAM-abhängigen Abbaus von TSC2 konnte trotz vielfältiger Herangehensweisen nicht nachgewiesen werden. Eine Phosphorylierung als Indikation einer Inaktivierung war ebenfalls nicht detektierbar. Auch die GAP Aktivität von TSC2 auf Rheb, wird in in vitro Versuchen durch die Interaktion mit PAM nicht vermindert. Durch eine Verminderung der TSC2 Expression mittels spezifischer siRNA zeigte sich, dass TSC2 nicht in die S1P-abhängige mTOR Aktivierung involviert ist. Auch regulatorische Proteinkinasen wie AKT, ERK oder PI3K, die durch S1P aktiviert werden können, sind an dem Signalweg nicht beteiligt, wie die Hemmung dieser Enzyme mit spezifischen Inhibitoren zeigte. Dagegen konnte eine Beteiligung von PAM und Rheb zum einen mittels Proteintransfektion bestätigt werden, zum anderen ließen sich die S1P Effekte durch Hemmstoffe verhindern, die für eine Aktivierung von PAM, respektive Rheb, nötig sind. Durch Nukleotidbindungsstudien war ein Einfluss von PAM auf den GTP-Beladungszustand von Rheb nachweisbar. Sowohl in einem GTPS Bindungsversuch als auch in einem GDP Dissoziationsexperiment erhöhte PAM konzentrationsabhängig die GTP Bindung bzw. den GDP/GTP Austausch an Rheb. In dieser Arbeit wird damit erstmalig eine duale Funktion eines Proteins als Ubiquitinligase und GEF beschrieben. So konnte die postulierte Aktivität von PAM als Ubiquitinligase bestätigt und TSC2 als Zielprotein identifiziert werden. Gleichzeitig wurde ein TSC2 unabhängiger Weg der mTOR Aktivierung aufgeklärt, an dem PAM und Rheb beteiligt sind. Als möglicher Mechanismus kommt eine Aktivität von PAM als Guanin-Nukleotid Austausch Faktor (GEF) auf Rheb in Frage. Durch Beschreibung von PAM als negativem Regulator von TSC2 und Aktivator von Rheb trägt diese Arbeit einen wichtigen Beitrag zur TSC2 / mTOR Forschung bei. Umgekehrt ermöglicht sie eine neue Sichtweise auf partiell PAM-abhängige Vorgänge wie Synaptogenese und Nozizeption, indem sie TSC2 / mTOR in diese Prozesse integriert.Protein Associated with Myc (PAM) is involved in a variety of physiological events. These include but are not limited to synaptogenesis, nociception as well as regulation of pteridine synthesis and cAMP metabolism. Until now, only few is known about the mechanisms by which PAM mediates those different effects. To elucidate the mechanism of action of PAM, different biochemical approaches very used in this thesis. Using in vitro biochemical assays, it could b shown, that PAM is an active E3-ubiqutine ligase. Both, the natively purified human PAM as well as the heterogeneously expressed C-terminal part (C-PAM) containing the catalytic active RING finger domain, were able to catalyse ubiquitinchain formation and autoubiquitination. During the identification process of potential target proteins, the TSC2 protein together with the linked TSC2-mTOR signaling attracted notice. An interaction of PAM and TSC2 could be shown using co-immunoprecipitation and immunocytochemistry in the chosen model system HeLa cells. It was shown for the very first time, that native, fulllength PAM but not the isolated RING finger domain can lead to polyubiquitination and proteasomal degradation of TSC2. By inhibiting the stimulatory Rheb protein, TSC2 is a negative regulator of the mTOR kinase activity. PAM is activated by the phospholipid Sphingosine 1 Phosphate (S1P) in HeLa cells. After S1P treatment, a phosphorylation of mTOR was detectable. This was accompanied by an activation of mTOR as shown by the rapamycine sensitive phosphorylation of the mTOR targets p70S6K and 4E-BP1. An involvement of the S1P1 as well as of the S1P3 receptor could ruled out by using S1P receptor agonists/antagonists. The expected mechanism of an S1P induced TSC2 degradation by PAM could not be validated. In addition, a phosphorylation of TSC2 was not detectable. Also the GAP activity of TSC2 towards Rheb was not altered in in vitro assays. Using TSC2 specifc siRNA is could be shown, that TSC2 is not involved in the S1P mediated mTOR activation. Regulatory kinases that can be activated by S1P such as AKT, ERK or PI3K are not involved as shown by inhibition of these enzymes using specific inhibitors. In contrast to this, an involvement of PAM and Rheb could be validated using proteintransfection, on the other hand were S1P mediated effects sensitive to inhibitors known to be necessary for an activation of PAM or Rheb respectively. Using nucleotide-binding and –exchange essays an impact of PAM on the GTP-level of Rheb was detectable. PAM enhanced the GDP/GTP exchange on Rheb in a GTPgS as well as in in GDP dissociation assay in a concentration dependent manner. In this thesis, a dual role of a protein as an E3-ubiquitin ligase and Guanine Nucleotide Exchange Factor (GEF) is described for the very first time. The postulated ligase activity of PAM was confirmed and TSC2 identified as a target protein. In parallel a TSC2 independent pathway leading to mTOR activation was identified. A GEF activity of PAM towards Rheb was found as a potential mechanism. By description of PAM as a negative regulator of TSC2 and an activator of Rheb, this thesis provides an important contribution to the field of TSC2-mTOR research. On the other hand new perceptions on PAM dependent events like synaptogenesis or nociception emerge by integrating TSC2-mTOR into these processes