Communicating Processes with Data for Supervisory Coordination

We employ supervisory controllers to safely coordinate high-level discrete(-event) behavior of distributed components of complex systems. Supervisory controllers observe discrete-event system behavior, make a decision on allowed activities, and communicate the control signals to the involved parties. Models of the supervisory controllers can be automatically synthesized based on formal models of the system components and a formalization of the safe coordination (control) requirements. Based on the obtained models, code generation can be used to implement the supervisory controllers in software, on a PLC, or an embedded (micro)processor. In this article, we develop a process theory with data that supports a model-based systems engineering framework for supervisory coordination. We employ communication to distinguish between the different flows of information, i.e., observation and supervision, whereas we employ data to specify the coordination requirements more compactly, and to increase the expressivity of the framework. To illustrate the framework, we remodel an industrial case study involving coordination of maintenance procedures of a printing process of a high-tech Oce printer.Comment: In Proceedings FOCLASA 2012, arXiv:1208.432

Dynamic plantar loading index detects altered foot function in individuals with rheumatoid arthritis but not changes due to orthotic use

Background Altered foot function is common in individuals with rheumatoid arthritis. Plantar pressure distributions during gait are regularly assessed in this patient group; however, the association between frequently reported magnitude-based pressure variables and clinical outcomes has not been clearly established. Recently, a novel approach to the analysis of plantar pressure distributions throughout stance phase, the dynamic plantar loading index, has been proposed. This study aimed to assess the utility of this index for measuring foot function in individuals with rheumatoid arthritis.Methods Barefoot plantar pressures during gait were measured in 63 patients with rheumatoid arthritis and 51 matched controls. Additionally, 15 individuals with rheumatoid arthritis had in-shoe plantar pressures measured whilst walking in standardized footwear for two conditions: shoes-only; and shoes with prescribed custom foot orthoses. The dynamic plantar loading index was determined for all participants and conditions. Patient and control groups were compared for significant differences as were the shod and orthosis conditions.Findings The patient group was found to have a mean index of 0.19, significantly lower than the control group's index of 0.32 (p > 0.001, 95% CI [0.054, 0.197]). No significant differences were found between the shoe-only and shoe plus orthosis conditions. The loading index was found to correlate with clinical measures of structural deformity.Interpretation The dynamic plantar loading index may be a useful tool for researchers and clinicians looking to objectively assess dynamic foot function in patients with rheumatoid arthritis; however, it may be unresponsive to changes caused by orthotic interventions in this patient group.</p

A Process Algebra for Supervisory Coordination

A supervisory controller controls and coordinates the behavior of different components of a complex machine by observing their discrete behaviour. Supervisory control theory studies automated synthesis of controller models, known as supervisors, based on formal models of the machine components and a formalization of the requirements. Subsequently, code generation can be used to implement this supervisor in software, on a PLC, or embedded microprocessor. In this article, we take a closer look at the control loop that couples the supervisory controller and the machine. We model both event-based and state-based observations using process algebra and bisimulation-based semantics. The main application area of supervisory control that we consider is coordination, referred to as supervisory coordination, and we give an academic and an industrial example, discussing the process-theoretic concepts employed.Comment: In Proceedings PACO 2011, arXiv:1108.145

Risk Factors for HSV-2 Infection among Sexual Partners of HSV-2/HIV-1 Co-Infected Persons

<p>Abstract</p> <p>Background</p> <p>Herpes simplex virus type 2 (HSV-2) is the most frequent cause of genital ulcer disease worldwide and has been associated with increased risk for HIV-1 acquisition and transmission. We conducted a cross-sectional analysis of risk factors for HSV-2 infection among HIV-1 uninfected partners, whose partners were co-infected with HIV-1 and HSV-2.</p> <p>Methods</p> <p>Between November 2004 and April 2007, 3408 HIV-discordant couples, in which the HIV-1 infected partners were HSV-2 seropositive with CD4 250 cells/mm³or greater, were enrolled in an HSV-2 suppression trial to prevent HIV-1 transmission at 14 sites in 7 African countries. Clinical & behavioral data, HSV-2 and HIV-1 testing were conducted at enrolment. Univariate and multivariate Poisson regression analyses were performed separately, by gender of the HIV-1 infected partner.</p> <p>Results</p> <p>Among 3354 HIV-1 uninfected participants, 32% were female and overall 71% were HSV-2 seropositive. Among couples with female HIV-1 infected partners, HIV-1 plasma RNA [aPR 1.03; 95% CI: 0.99 to 1.06; p = 0.11] and CD4 count [aPR 1.00; 95% CI: 0.98 to 1.01; p = 0.48] in the HSV-2/HIV-1 dually infected female and circumcision in the HIV-1 uninfected male partner [aPR 0.94; 95% CI: 0.88 to 1.00; p = 0.06] were not associated with reduced risk of HSV-2 seropositivity, after adjusting for other factors.</p> <p>Conclusions</p> <p>In this cross-sectional analysis of African HIV-1 serodiscordant heterosexual couples with prevalent HSV-2 infection in the HIV-1 infected partner, HIV-1 plasma RNA and CD4 count in the dually-infected partner and male circumcision in the HIV-1 uninfected partner were not associated with HSV-2 concordance.</p> <p>Trial Registration</p> <p>ClinicalTrials.gov <a href="http://www.clinicaltrials.gov/ct2/show/NCT00194519">NCT00194519</a></p

The use of neural network algorithms for the classification of undifferentiated arthritis by synovial histopathology

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Linearization of CIF Through SOS

Linearization is the procedure of rewriting a process term into a linear form, which consist only of basic operators of the process language. This procedure is interesting both from a theoretical and a practical point of view. In particular, a linearization algorithm is needed for the Compositional Interchange Format (CIF), an automaton based modeling language. The problem of devising efficient linearization algorithms is not trivial, and has been already addressed in literature. However, the linearization algorithms obtained are the result of an inventive process, and the proof of correctness comes as an afterthought. Furthermore, the semantic specification of the language does not play an important role on the design of the algorithm. In this work we present a method for obtaining an efficient linearization algorithm, through a step-wise refinement of the SOS rules of CIF. As a result, we show how the semantic specification of the language can guide the implementation of such a procedure, yielding a simple proof of correctness.Comment: In Proceedings EXPRESS 2011, arXiv:1108.407