Network algebra for synchronous dataflow

We develop an algebraic theory of synchronous dataflow networks. First, a basic algebraic theory of networks, called BNA (Basic Network Algebra), is introduced. This theory captures the basic algebraic properties of networks. For synchronous dataflow networks, it is subsequently extended with additional constants for the branching connections that occur between the cells of synchronous dataflow networks and axioms for these additional constants. We also give two models of the resulting theory, the one based on stream transformers and the other based on processes as considered in process algebra.Comment: 24 page

Antiinflammatory Therapy with Canakinumab for Atherosclerotic Disease

Background: Experimental and clinical data suggest that reducing inflammation without affecting lipid levels may reduce the risk of cardiovascular disease. Yet, the inflammatory hypothesis of atherothrombosis has remained unproved. Methods: We conducted a randomized, double-blind trial of canakinumab, a therapeutic monoclonal antibody targeting interleukin-1β, involving 10,061 patients with previous myocardial infarction and a high-sensitivity C-reactive protein level of 2 mg or more per liter. The trial compared three doses of canakinumab (50 mg, 150 mg, and 300 mg, administered subcutaneously every 3 months) with placebo. The primary efficacy end point was nonfatal myocardial infarction, nonfatal stroke, or cardiovascular death. RESULTS: At 48 months, the median reduction from baseline in the high-sensitivity C-reactive protein level was 26 percentage points greater in the group that received the 50-mg dose of canakinumab, 37 percentage points greater in the 150-mg group, and 41 percentage points greater in the 300-mg group than in the placebo group. Canakinumab did not reduce lipid levels from baseline. At a median follow-up of 3.7 years, the incidence rate for the primary end point was 4.50 events per 100 person-years in the placebo group, 4.11 events per 100 person-years in the 50-mg group, 3.86 events per 100 person-years in the 150-mg group, and 3.90 events per 100 person-years in the 300-mg group. The hazard ratios as compared with placebo were as follows: in the 50-mg group, 0.93 (95% confidence interval [CI], 0.80 to 1.07; P = 0.30); in the 150-mg group, 0.85 (95% CI, 0.74 to 0.98; P = 0.021); and in the 300-mg group, 0.86 (95% CI, 0.75 to 0.99; P = 0.031). The 150-mg dose, but not the other doses, met the prespecified multiplicity-adjusted threshold for statistical significance for the primary end point and the secondary end point that additionally included hospitalization for unstable angina that led to urgent revascularization (hazard ratio vs. placebo, 0.83; 95% CI, 0.73 to 0.95; P = 0.005). Canakinumab was associated with a higher incidence of fatal infection than was placebo. There was no significant difference in all-cause mortality (hazard ratio for all canakinumab doses vs. placebo, 0.94; 95% CI, 0.83 to 1.06; P = 0.31). Conclusions: Antiinflammatory therapy targeting the interleukin-1β innate immunity pathway with canakinumab at a dose of 150 mg every 3 months led to a significantly lower rate of recurrent cardiovascular events than placebo, independent of lipid-level lowering. (Funded by Novartis; CANTOS ClinicalTrials.gov number, NCT01327846.

Processes with Multiple Entries and Exits

This paper is an attempt to integrate the algebra of communicating processes (ACP) and the algebra of ownomials (AF). Basically, this means to combine axiomatized parallel and looping operators. To this end we introduce a model of process graphs with multiple entries and exits. In this model the usual operations of both algebras are dened, e.g. alternative composition (this covers both the sum of ACP and the disjoint sum of AF), sequential composition, feedback, parallel composition, left merge, communication merge, encapsulation, etc. The main results consist of correct and complete axiomatisations of process graphs modulo isomorphism and modulo bisimulation. Key words & Phrases: process algebra, feedback, owchart theories.

Mixed relations as enriched semiringal categories

Abstract: A study of the classes of nite relations as enriched strict monoidal categories is presented in [CaS91]. The relations there are interpreted as connections in owchart schemes, hence an \angelic " theory of relations is used. Finite relations may be used to model the connections between the components of data ow networks [BeS98, BrS96], as well. The corresponding algebras are slightly di erentenriched strict monoidal categories modeling a \forward-demonic " theory of relations. In order to obtain a full model for parallel programs one needs to mix control and reactive parts, hence a richer theory of nite relations is needed. In this paper we (1) de ne a model of such mixed nite relations, (2) introduce enriched (weak) semiringal categories as an abstract algebraic model for these relations, and (3) show that the initial model of the axiomatization (it always exists) is isomorphic to the de ned one of mixed relations. Hence the axioms gives a sound and complete axiomatization for the these relations. Key Words: parallel programs � mixed relations � network algebra � (enriched) semiringa

Network Algebra for Asynchronous Dataflow

Network algebra is proposed as a uniform algebraic framework for the description and analysis of dataflow networks. An equational theory of networks, called BNA (Basic Network Algebra), is presented. BNA, which is essentially a part of the algebra of flownomials, captures the basic algebraic properties of networks. For asynchronous dataflow networks, additional constants and axioms are given; and a corresponding process algebra model is introduced. This process algebra model is compared with previous models for asynchronous dataflow. Keywords & Phrases: dataflow networks, network algebra, process algebra, asynchronous dataflow, feedback, merge anomaly, history models, oracle based models, trace models. 1994 CR Categories: F.1.1, F.1.2, F.3.2., D.1.3., D.3.1. This paper is an abridged version of [1]. The full version covers synchronous dataflow networks as well. y Partially supported by ESPRIT BRA 8533 (NADA) and ESPRIT BRA 6454 (CONFER). x On leave (1996--1997) at Unit..

Network Algebra for Synchronous and Asynchronous Dataflow

Network algebra is proposed as a uniform algebraic framework for the description and analysis of dataflow networks. An equational theory, called BNA (Basic Network Algebra), is presented. BNA, which is essentially a part of the algebra of flownomials, captures the basic algebraic properties of networks. For synchronous and asynchronous dataflow networks, additional constants and axioms for connections are given; and corresponding process algebra models are introduced. The main difference between these models is in the interpretation of the identity connections, called wires in dataflow networks. The process algebra model for the asynchronous case is compared with previous models. Keywords & Phrases: dataflow networks, network algebra, process algebra, asynchronous dataflow, synchronous dataflow, feedback, merge anomaly, history models, oracle based models, trace models. 1994 CR Categories: F.1.1, F.1.2, F.3.2., D.1.3., D.3.1. y The first author has been partially supported by ESPRIT..