Runtime verification of parametric properties using SMEDL

Parametric properties are typical properties to be checked in runtime verification (RV). As a common technique for parametric monitoring, trace slicing divides an execution trace into a set of sub traces which are checked against non-parametric base properties. An efficient trace slicing algorithm is implemented in MOP. Another RV technique, QEA further allows for nested use of universal and existential quantification over parameters. In this paper, we present a methodology for parametric monitoring using the RV framework SMEDL. Trace slicing algorithm in MOP can be expressed by execution of a set of SMEDL monitors. Moreover, the semantics of nested quantifiers is encoded by a hierarchy of monitors for aggregating verdicts of sub traces. Through case studies, we demonstrate that SMEDL provides a natural way to monitor parametric properties with more potentials for flexible deployment and optimizations

pH Effects in Foods: Development, Validation and Calibration of a Fundamental Model

The effects of pH observed in the activity of a number of enzymes from different origins and the degradation of green colour in blanched vegetables, was modelled based on fundamental kinetic principles by considering hydrogen ions as an integral part of the reaction mechanism. Parameters were estimated by non-linear regression analysis with explained parts (R2adj) was in all cases except for the enzyme lipase, well over 95°and frequently well over 98&Eth;Applying fundamental models in integral data analysis made it possible to pinpoint aberrations at high and low pH ranges in the discoloration of vegetables, which remained unnoticed using classical analysis procedures. The model on enzyme activity was successfully applied to analyse and to describe a double optimal pH region when iso-enzymes are present in the total pool of active enzymes

Monitoring Time Intervals

Run-time checking of timed properties requires to monitor events occurring within a specified time interval. In a distributed setting, working with intervals is complicated due to uncertainties about network delays and clock synchronization. Determining that an interval can be closed - i.e., that all events occurring within the interval have been observed - cannot be done without a delay. In this paper, we consider how an appropriate delay can be determined based on parameters of a monitoring setup, such as network delay, clock skew and clock rate. We then propose a generic scheme for monitoring time intervals, parameterized by the detection delay, and discuss the use of this monitoring scheme to check different timed specifications, including real-time temporal logics and rate calculations

Correct-by-construction implementation of runtime monitors using stepwise refinement

Runtime verification (RV) is a lightweight technique for verifying traces of computer systems. One challenge in applying RV is to guarantee that the implementation of a runtime monitor correctly detects and signals unexpected events. In this paper, we present a method for deriving correct-by-construction implementations of runtime monitors from high-level specifications using Fiat, a Coq library for stepwise refinement. SMEDL (Scenario-based Meta-Event Definition Language), a domain specific language for event-driven RV, is chosen as the specification language. We propose an operational semantics for SMEDL suitable to be used in Fiat to describe the behavior of a monitor in a relational way. Then, by utilizing Fiat\u27s refinement calculus, we transform a declarative monitor specification into an executable runtime monitor with a proof that the behavior of the implementation is strictly a subset of that provided by the specification. Moreover, we define a predicate on the syntax structure of a monitor definition to ensure termination and determinism. Most of the proof work required to generate monitor code has been automated

Dietary supplementation by older adults in southern China: a hospital outpatient clinic study

<p>Abstract</p> <p>Background</p> <p>There has been little knowledge about dietary supplementation by the Chinese elderly. The aim of this cross-sectional study was to investigate the usage of dietary supplements by older adults in southern China.</p> <p>Methods</p> <p>A total of 600 community-dwelling older adults were recruited from the outpatient clinics of three major hospitals in Foshan city between July 2007 and July 2008. Face-to-face interviews of participants were conducted to obtain information on demographics, lifestyle and dietary supplements use. Frequency and duration of usage were recorded for six categories of dietary supplements.</p> <p>Results</p> <p>Among the 446 consented participants (241 men and 205 women) who were over 55 years of age, 19.1% consumed one or more types of dietary supplements. The prevalence of usage was significantly higher (p = 0.008) for females (24.4%) than for males (14.5%). Dietary supplements were more likely to be consumed by non-smokers (p = 0.021) and those with hyperlipidemia (p = 0.003). The most popular supplement among users was calcium (53%). The majority (71%) of the users consumed supplements on a regular basis at one or more times per day, with an average duration of 2.95 (SD 4.80) years.</p> <p>Conclusion</p> <p>The overall prevalence of dietary supplementation in this older Chinese population was considerably lower than those in other Asia-Pacific countries.</p