Domain Theory for Concurrency

A simple domain theory for concurrency is presented. Based on a categorical model of linear logic and associated comonads, it highlights the role of linearity in concurrent computation. Two choices of comonad yield two expressive metalanguages for higher-order processes, both arising from canonical constructions in the model. Their denotational semantics are fully abstract with respect to contextual equivalence. One language derives from an exponential of linear logic; it supports a straightforward operational semantics with simple proofs of soundness and adequacy. The other choice of comonad yields a model of affine-linear logic, and a process language with a tensor operation to be understood as a parallel composition of independent processes. The domain theory can be generalised to presheaf models, providing a more refined treatment of nondeterministic branching. The article concludes with a discussion of a broader programme of research, towards a fully fledged domain theory for concurrency

Estimating Multivariate Exponentail-Affine Term Structure Models from Coupon Bound Prices using Nonlinear Filtering

An econometric analysis of continuous-time models of the term structure of interest rates is presented. A panel of coupon bond prices with different maturities is used to estimate the embedded parameters of a continuous-discrete state space model of unobserved state variables: the spot interest rate, the central tendency and stochastic volatility. Emphasis is placed on the particular class of exponential-affine term structure models that permits solving the bond pricing PDE in terms of a system of ODEs. It is assumed that coupon bond prices are contaminated by additive white noise, where the stochastic noise term should account for model errors. A nonlinear filtering method is used to compute estimates of the state variables, and the model parameters are estimated by a quasimaximum likelihood method provided that some assumptions are imposed on the model residuals. Both Monte Carlo simulation results and empirical results based on the Danish bond market are presented

A cross-sectional comparison of performance, neurophysiological and MRI outcomes of responders and non-responders to fampridine treatment in multiple sclerosis - An explorative study

OBJECTIVE: To compare baseline physical and cognitive performance, neurophysiological, and magnetic resonance imaging (MRI) outcomes and examinetheir interrelationship inparticipants with Multiple Sclerosis (MS), already established aseither responder or non-responder to Fampridine treatment, andto examine associationswiththe expanded disability status scale (EDSS) and 12-item MS walking scale (MSWS-12). METHODS: Baseline data from an explorative longitudinal observational study were analyzed. Participants underwent the Timed 25-Foot Walk Test (T25FW), Six Spot Step Test (SSST), Nine-Hole Peg Test, Five Times Sit-to-Stand Test, Symbol Digit Modalities Test (SDMT), neurophysiological testing, including central motor conduction time (CMCT), peripheral motor conduction time (PMCT), motor evoked potential (MEP) amplitudesand electroneuronographyof the lower extremities, and brain MRI (brain volume, number and volume of T2-weighted lesions and lesion load normalized to brain volume). RESULTS: 41 responders and 8 non-responders were examined. There were no intergroup differences inphysical performance, cognitive, neurophysiological, andMRI outcomes (p > 0.05).CMCT was associated withT25FW, SSST, EDSS, and MSWS-12,(p < 0.05). SDMT was associated with the number and volume of T2-weighted lesions, and lesion load normalized to brain volume (p < 0.05). CONCLUSION: No differences were identified between responders and non-responders to Fampridine treatment regarding physical and cognitive performance, neurophysiological or MRI outcomes. The results call for cautious interpretation and further large-scale studies are needed to expand ourunderstanding of underlying mechanisms discriminating Fampridine responders and non-responders.CMCT may be used as a marker of disability and walking impairment, while SDMT was associated with white matter lesions estimated by MRI. ClinicalTrials.gov identifier: NCT03401307

Domain theory for concurrency

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Towards an Operational Understanding of Presheaf Models

This document reports on progress towards an operational understanding of presheaf models. With their built in notion of open-map bisimulation, presheaf models have been put forward as providing a domain theory for concurrency. An accompanying metalanguage in which terms are interpreted by profunctors between partial orders (with closed terms denoting presheaves) was proposed by Winskel in [21]. Our contributions fall in two parts: First, we give an SOS style operational semantics to a first-order fragment of the metalanguage and establish an isomorphism between derivations and elements of presheaves. Second, by representing the profunctors that interpret open terms with prime event structures, a new denotational semantics of the same fragment is given. With this representation, elements of presheaves can be understood as configurations of event structures with prime configurations corresponding to the derivations of the operational semantics

This document in subdirectoryRS/02/49/ HOPLA—A Higher-Order Process Language

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