1,922 research outputs found
NLC Luminosity as a Function of Beam Parameters
Realistic calculation of NLC luminosity has been performed using particle
tracking in DIMAD and beam-beam simulations in GUINEA-PIG code for various
values of beam emittance, energy and beta functions at the Interaction Point
(IP). Results of the simulations are compared with analytic luminosity
calculations. The optimum range of IP beta functions for high luminosity was
identified.Comment: 4 pages, 7 figure
Simulation Studies of the NLC with Improved Ground Motion Models
The performance of various systems of the Next Linear Collider (NLC) have
been studied in terms of ground motion using recently developed models. In
particular, the performance of the beam delivery system is discussed. Plans to
evaluate the operation of the main linac beam-based alignment and feedback
systems are also outlined.Comment: Submitted to XX International Linac Conferenc
Tuning Knobs for the NLC Final Focus
Compensation of optics errors at the Interaction Point (IP) is essential for
maintaining maximum luminosity at the NLC. Several correction systems (knobs)
using the Final Focus sextupoles have been designed to provide orthogonal
compensation of linear and the second order optics aberrations at IP. Tuning
effects of these knobs on the 250 GeV beam were verified using tracking
simulations.Comment: 4 pages, 3 figure
Beam-based Feedback Simulations for the NLC Linac
Extensive beam-based feedback systems are planned as an integral part of the
Next Linear Collider (NLC) control system. Wakefield effects are a significant
influence on the feedback design, imposing both architectural and algorithmic
constraints. Studies are in progress to assure the optimal selection of devices
and to refine and confirm the algorithms for the system design. We show the
results of initial simulations, along with evaluations of system response for
various conditions of ground motion and other operational disturbances.Comment: 3 pages. Linac2000 conferenc
Slrtool: a tool to support collaborative systematic literature reviews
Systematic Literature Reviews (SLRs) are used in a number of fields to produce unbiased accounts of specific research topics. The SLR process is particularly well documented and regulated in the medical field, where it is accepted as the standard mechanism to assess, for instance, the benefits of drugs and treatments. SLRs and meta-analysis techniques are increasingly being used in other fields as well, from Social Sciences to Software Engineering
The packing chromatic number of the infinite square lattice is between 13 and 15
Using a SAT-solver on top of a partial previously-known solution we improve the upper bound of the packing chromatic number of the infinite square lattice from 17 to 15. We discuss the merits of SAT-solving for this kind of problem as well as compare the performance of different encodings. Further, we improve the lower bound from 12 to 13 again using a SAT-solver, demonstrating the versatility of this technology for our approach
A proof-theoretic trust and reputation model for VANET
Vehicular Ad Hoc Networks (VANETs) are an important component of intelligent transportation systems, which are set to become part of global transportation infrastructure in the near future. In the context of such networks, security requirements need to rely on a combination of reputation of communicating agents and trust relations over the messaging framework. This is crucial in order to maintain dynamic and safe behaviour under all circumstances. Formal correctness, resolution of contradictions and proven safety of transitive operations in the presence of reputation and trust within the infrastructure remain mostly unexplored issues. This could lead to potentially disastrous situations, putting lives at risk. In this paper we provide a proof-theoretic interpretation of a reputation and trust model for VANET. This allows for formal verification through translation into the Coq proof assistant, and can guarantee consistency of messaging protocols and security of transitive transmissions
A computationally grounded, weighted doxastic logic
Modelling, reasoning and verifying complex situations involving a system of agents is crucial in all phases of the development of a number of safety-critical systems. In particular, it is of fundamental importance to have tools and techniques to reason about the doxastic and epistemic states of agents, to make sure that the agents behave as intended. In this paper we introduce a computationally grounded logic called COGWED and we present two types of semantics that support a range of practical situations. We provide model checking algorithms, complexity characterisations and a prototype implementation. We validate our proposal against a case study from the avionic domain: we assess and verify the situational awareness of pilots flying an aircraft with several automated components in off-nominal conditions
CoSMed: a confidentiality-verified social media platform
This paper describes progress with our agenda of formal verification of information-flow security for realistic systems. We present CoSMed, a social media platform with verified document confidentiality. The system’s kernel is implemented and verified in the proof assistant Isabelle/HOL. For verification, we employ the framework of Bounded-Deducibility (BD) Security, previously introduced for the conference system CoCon. CoSMed is a second major case study in this framework. For CoSMed, the static topology of declassification bounds and triggers that characterized previous instances of BD security has to give way to a dynamic integration of the triggers as part of the bound
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