The smes client/server protocol (SMESPR/1.0)

SMESPR is a robust, efficient, flexible and platform/language independent protocol that allows the smes kernel to export its functionality over any sort of computer networks (in particular TCP/IP). It allows for results in different formats (HTML/XML, SQL and plain feature structures are available, others may be easily added) as well as for creating and controlling graphical user interfaces from the interior of the smes world. Furthermore, any sort of access or privacy policy can be plugged into the existing protocol very easily. A prototype implementation is in use at the DFKI in several projects. This article contains the documentation of SMESPR/1.0 and out prototype implementation

Conformally covariant differential operators acting on spinor bundles and related conformal covariants

Konforme Potenzen des Dirac Operators einer semi Riemannschen Spin-Mannigfaltigkeit werden untersucht. Wir präsentieren einen neuen Beweis, basierend auf dem Traktor Kalkül, für die Existenz von konformen ungeraden Potenzen des Dirac Operators auf semi Riemannschen Spin-Mannigfaltigkeiten. Desweiteren konstruieren wir eine neue Familie von konform kovarianten linearen Differentialoperatoren auf dem standard spin Traktor Bündel. Weiterhin verallgemeinern wir den Existenzbeweis für konforme ungerade Potenzen des Dirac Operators auf semi Riemannsche Spin-Mannigfaltigkeiten. Da die Existenzbeweise konstruktive sind, erhalten wir explizite Formeln für die konforme dritte und fünfte Potenz des Dirac Operators. Basierend auf den expliziten Formeln zeigen wir, dass die konforme dritte und fünfte Potenz des Dirac Operators formal selbstadjungiert (anti selbstadjungiert) bezüglich des L2-Skalarproduktes auf dem Spinorbündel ist. Abschliessend präsentieren wir neue Strukturen der konformen ersten, dritten und fünften Potenz des Dirac Operators: Es existieren lineare Differentialoperatoren auf dem Spinorbündel der Ordnung kleiner gleich eins, so dass die konforme erste, dritte und fünfte Potenz des Dirac Operators ein Polynom in jenen Operatoren ist.Conformal powers of the Dirac operator on semi Riemannian spin manifolds are investigated. We give a new proof of the existence of conformal odd powers of the Dirac operator on semi Riemannian spin manifolds using the tractor machinery. We will also present a new family of conformally covariant linear differential operators on the standard spin tractor bundle. Furthermore, we generalize the known existence proof of conformal power of the Dirac operator on Riemannian spin manifolds to semi Riemannian spin manifolds. Both proofs concering the existence of conformal odd powers of the Dirac operator are constructive, hence we also derive an explicit formula for a conformal third- and fifth power of the Dirac operator. Due to explicit formulas, we show that the conformal third- and fifth power of the Dirac operator is formally self-adjoint (anti self-adjoint), with respect to the L2-scalar product on the spinor bundle. Finally, we present a new structure of the conformal first-, third- and fifth power of the Dirac operator: There exist linear differential operators on the spinor bundle of order less or equal one, such that the conformal first-, third- and fifth power of the Dirac operator is a polynomial in these operators

Synergien nutzen: Wie die MES-Entwicklung von Werkzeugen der Logistikplanung profitieren kann

Today, simulation studies are an inherent part of the logistics planner´s toolbox. However, the costs for creating and maintaining simulation models are challenged every now and then. This paper describes an approach that allows IT-departments in charge of developing and operating Manufacturing Execution Systems (MES) to benefit from simulation models that have originally been created for logistics planning. Thus, it opens an additional field of application for these models and the possibility to use the investments in simulation more efficiently

On dialogues and ontology the dialogical approach to free logic

International audienceBeing a pragmatic and not a referential approach to semantics, dialogi-cal logic does not understand semantics as mapping names, propositions and relationships into the real world to obtain an abstract counterpart of it, but as dealing (handeln) with them in a particular way. This allows a very simple formulation of free logic the core of which can be expressed in a nutshell, namely: in an argumentation, it sometimes makes sense to restrict the introduction of singular terms in the context of quantification to a formal use o f them. That is, the proponent is allowed to use a constant if f this constant has been explicitly conceded by the opponent. More technically, we show a new, dialogical way to build free logic systems fo r first-order logic with classical and intuitionistic features and present their corresponding tableaux. I. In tro d u ctio n I I. F r e e logics ON DIALOGUES A ND ONTOLOGY THE DIAL OGICAL APPROACH TO FREE LOGIC The proposition "God does not exist" contains a paradox sometimes referred to as Plato's beard: if God does not exist and the proposition should be true, standard referential semantics fo r quantified logic fails to give meaning to the name "God". But, given compositionality, since the meaning of a sentence is combined from the meanings o f its parts,-G o d d o e s not exist" does not evaluate. It is easy to see that related difficulties appear in every formula that contains singular terms. In standard logic, it is impossible to state that God is either good or evil without presupposing his existence, or that the round * My work on this article has been supported by the Fritz-Thyssen-Stiftung which I wish to thank expressly

Data confidentiality and reputation schemes in distributed information systems

Diese Arbeit betrachtet zwei anspruchsvolle Probleme aus dem Bereich Computer- und Kommunikationssicherheit und Vertrauen. Beim Datenbank-Serviceprovider-Problem moechte ein Anwender seine Datenbank an einen Datenbank-Serviceprovider (DSP) uebergeben, damit dieser sie betreiben und ihm zur Verfuegung stellen kann. Er vertraut diesem DSP, und damit auch vertraglichen Abmachungen, nur bedingt und muss die Vertraulichkeit seiner Daten durch technische Massnahmen sicherstellen. Das zweite Problem ist das Verbreiten verlaesslicher Reputationsinformation ueber eine (moeglicherweise sehr grosse) Anzahl von Netzwerk-Knoten in einer Peer-to-Peer-Umgebung (P2P). Beide Probleme straeuben sich hartnaeckig gegen einfache Loesungen. Im Gegensatz zu traditionellen Sicherheitsproblemen in der Informatik hat der Gegner in beiden ein hohes Mass an Kontrolle ueber die Situation. Der nicht ausreichend vertrauenswuerdige DSP muss in der Lage sein, die Daten seines Kunden zu verarbeiten, ohne etwas ueber sie zu lernen, was intuitiv wie ein Widerspruch erscheint. In P2P-Anwendungen ist es wuenschenswert, dass Knoten anonym beitreten und jederzeit wieder austreten koennen, aber diese Anonymitaet erleichtert es, falsche Reputationsinformation zu verbreiten. Ein Knoten, der erstmalig in ein P2P-Netzwerk eintritt, muss den behaupteten Beobachtungen anderer Knoten vertrauen. Die Resultate dieser Arbeit sind keine Idealloesungen, und dennoch aufschlussreich in mehrerlei Hinsicht: Es werden gelockerte, aber immer noch nuetzliche Sicherheitsbegriffe fuer das DSP-Problem vorgeschlagen; es werden theoretische Grenzen des DSP-Loesungsraums gezogen; und die Auswirkung feindseligen Verhaltens in P2P-Reputationssystemen wird durch heuristische Methoden reduziert. Ein Nebeneffekt unserer Arbeit ist ein speziell fuer Reputationssysteme in P2P-Netzwerken geeignetes Simulations-Tool, das zum Vergleich und zum Fine-Tuning bestehender und zukuenftiger Forschungsarbeiten genutzt werden kann.In this thesis we discuss two demanding problems from the field of computer and communication security that involve trust. The first is known as the database service provider problem: A database owner wants a database service provider (DSP) to host her database. She only trusts this DSP to a limited extent, so she does not want to rely solely on contractual solutions. It is therefore necessary to enforce confidentiality of her data by technical means. The second problem concerns a (potentially very large) number of network nodes in a peer-to-peer (P2P) environment. Both problems are notoriously hard because, other than in traditional computer security problems, the adversary has a lot of control over the situation. The untrusted DSP needs to be able to process the data without learning anything about it, which seems to be a contradiction. In P2P applications it is desirable that nodes can join anonymously, but anonymity makes it easy to spread false reputation information. A node that enters a P2P application network for the first time needs to trust the claimed observations of other nodes, independent of the rate of malicious behaviour. Our findings are not perfect solutions, but nevertheless instructive in several ways: We propose relaxed, but still practically useful, notions of security for the DSP problem; we identify theoretical limitations of the DSP solution space; and we gradually reduce the impact of adversarial behaviour in P2P reputation systems using heuristic methods. As a side effect of our work, we present a special-purpose framework for simulation of P2P reputation systems that can be used to compare and fine-tune previous and upcoming work