353 research outputs found

    Holographic Composite Higgs Model Building: Soft Breaking, Maximal Symmetry, and the Higgs Mass

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    We study the emergence and phenomenological consequences of recently proposednew structures, namely soft breaking of the Higgs shift symmetry and `maximalsymmetry' of the composite sector, in holographic realizations of compositeHiggs models. For the former, we show that soft breaking can also successfullybe implemented in a full 5D warped model, where symmetry-restoring universalboundary conditions for the fermion fields allow to break the problematicconnection between a realistically light Higgs and anomalously light toppartners. For the latter, we demonstrate that the minimal incarnation ofmaximal symmetry in the holographic dual leads to a sharp prediction ofmh197m_h\approx 197 GeV for f=800f=800 GeV. We find that a viable implementation ispossible with sizable negative gauge brane kinetic terms, allowing formh=125m_h=125 GeV. Overall, both approaches offer promising directions to improvethe naturalness also of holographic realizations of composite Higgs models.<br

    Mobile technologies in foreign language learning

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    Welding with laser beams is an innovative optical technique, which leads to higher penetration depth and a narrower seam compared to conventional welding techniques. Significant criteria of the quality of a junction besides detected faults are the penetration depth and the seam width. Within this article optical sensors for process monitoring as well as a predictive control scheme based on these are presented. In the closed loop control the process' inputs laser power and focal position are optimised by taking the future welding speed into account. For modelling the physical demanding, non-linear process an Artificial Neural Network with external dynamics is applied. First results of the application on a real laser welding system are described

    Synthesizing Finite-state Protocols from Scenarios and Requirements

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    Scenarios, or Message Sequence Charts, offer an intuitive way of describing the desired behaviors of a distributed protocol. In this paper we propose a new way of specifying finite-state protocols using scenarios: we show that it is possible to automatically derive a distributed implementation from a set of scenarios augmented with a set of safety and liveness requirements, provided the given scenarios adequately \emph{cover} all the states of the desired implementation. We first derive incomplete state machines from the given scenarios, and then synthesis corresponds to completing the transition relation of individual processes so that the global product meets the specified requirements. This completion problem, in general, has the same complexity, PSPACE, as the verification problem, but unlike the verification problem, is NP-complete for a constant number of processes. We present two algorithms for solving the completion problem, one based on a heuristic search in the space of possible completions and one based on OBDD-based symbolic fixpoint computation. We evaluate the proposed methodology for protocol specification and the effectiveness of the synthesis algorithms using the classical alternating-bit protocol.Comment: This is the working draft of a paper currently in submission. (February 10, 2014

    Propositional Dynamic Logic for Message-Passing Systems

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    We examine a bidirectional propositional dynamic logic (PDL) for finite and infinite message sequence charts (MSCs) extending LTL and TLC-. By this kind of multi-modal logic we can express properties both in the entire future and in the past of an event. Path expressions strengthen the classical until operator of temporal logic. For every formula defining an MSC language, we construct a communicating finite-state machine (CFM) accepting the same language. The CFM obtained has size exponential in the size of the formula. This synthesis problem is solved in full generality, i.e., also for MSCs with unbounded channels. The model checking problem for CFMs and HMSCs turns out to be in PSPACE for existentially bounded MSCs. Finally, we show that, for PDL with intersection, the semantics of a formula cannot be captured by a CFM anymore

    Propositional Dynamic Logic with Converse and Repeat for Message-Passing Systems

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    The model checking problem for propositional dynamic logic (PDL) over message sequence charts (MSCs) and communicating finite state machines (CFMs) asks, given a channel bound BB, a PDL formula φ\varphi and a CFM C\mathcal{C}, whether every existentially BB-bounded MSC MM accepted by C\mathcal{C} satisfies φ\varphi. Recently, it was shown that this problem is PSPACE-complete. In the present work, we consider CRPDL over MSCs which is PDL equipped with the operators converse and repeat. The former enables one to walk back and forth within an MSC using a single path expression whereas the latter allows to express that a path expression can be repeated infinitely often. To solve the model checking problem for this logic, we define message sequence chart automata (MSCAs) which are multi-way alternating parity automata walking on MSCs. By exploiting a new concept called concatenation states, we are able to inductively construct, for every CRPDL formula φ\varphi, an MSCA precisely accepting the set of models of φ\varphi. As a result, we obtain that the model checking problem for CRPDL and CFMs is still in PSPACE

    Explicit connection actions in multiparty session types

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    This work extends asynchronous multiparty session types (MPST) with explicit connection actions to support protocols with op- tional and dynamic participants. The actions by which endpoints are connected and disconnected are a key element of real-world protocols that is not treated in existing MPST works. In addition, the use cases motivating explicit connections often require a more relaxed form of mul- tiparty choice: these extensions do not satisfy the conservative restric- tions used to ensure safety in standard syntactic MPST. Instead, we de- velop a modelling-based approach to validate MPST safety and progress for these enriched protocols. We present a toolchain implementation, for distributed programming based on our extended MPST in Java, and a core formalism, demonstrating the soundness of our approach. We discuss key implementation issues related to the proposed extensions: a practi- cal treatment of choice subtyping for MPST progress, and multiparty correlation of dynamic binary connections

    Asynchronous Games over Tree Architectures

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    We consider the task of controlling in a distributed way a Zielonka asynchronous automaton. Every process of a controller has access to its causal past to determine the next set of actions it proposes to play. An action can be played only if every process controlling this action proposes to play it. We consider reachability objectives: every process should reach its set of final states. We show that this control problem is decidable for tree architectures, where every process can communicate with its parent, its children, and with the environment. The complexity of our algorithm is l-fold exponential with l being the height of the tree representing the architecture. We show that this is unavoidable by showing that even for three processes the problem is EXPTIME-complete, and that it is non-elementary in general

    Metric-like Lagrangian Formulations for Higher-Spin Fields of Mixed Symmetry

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    We review the structure of local Lagrangians and field equations for free bosonic and fermionic gauge fields of mixed symmetry in flat space. These are first presented in a constrained setting extending the metric formulation of linearized gravity, and then the (γ\gamma-)trace constraints on fields and gauge parameters are eliminated via the introduction of auxiliary fields. We also display the emergence of Weyl-like symmetries in particular classes of models in low space-time dimensions.Comment: 136 pages, LaTeX. References added. Final version to appear in La Rivista del Nuovo Cimento

    White Blood, Black Gold: The Commodification of Wild Rubber in the Bolivian Amazon, 1870-1920

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    The Bolivian rubber boom thrived during the 1880 and 1920 decades throughout the Amazonian fluvial network (Madre de Dios, Beni, Purús, Madeira and Beni rivers). The economic potential of rubber quickly became a decisive phenomenon in the social history of Eastern Bolivia, linked with the definitive ocupation of marginal territories, new interethnic relations, national and international migration, taxation, property entitlement, the foundation of cities, the rise of nationalism, the struggle to settle republican frontiers and a novel regional opening to global economy. The boom also encouraged substantial developments in cartography, hidrography, botanics and ethnology. Our goal is to describe the singularities of the rubber-tapping industry in Bolivia and to analyse the representations of “nature” held by rubber tappers of the period: there was indeed a modernist discourse based on the usual ideas of "progress" and "civilization" of the industry opposed to the "wildness", "savagery" and "barbarism" massively attributed to Amazonia, and also a generalized notion of the jungle as a "desert land" open to opportunities for the self-made man. In retrospect, these discourses can certainly reveal a lack of “ecological awareness”. However, a closer analysis of historical sources also shows the existence of voices that were more nuanced and reflexive, and in some cases even dared to point out the limits of extractivism –not only in "ecological" terms but also in reference to the life of the indigenous and creole populations involved in the rubber boom
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