466 research outputs found
From Interaction Overview Diagrams to Temporal Logic
In this paper, we use UML Interaction Overview Diagrams as the basis for a user-friendly, intuitive, modeling notation that is well-suited for the design of complex, heterogeneous, embedded systems developed by domain experts with little background on modeling software-based systems.
To allow designers to precisely analyze models written with this notation, we provide (part of) it with a formal semantics based on temporal logic, upon which a fully automated, tool supported, verification technique is built.
The modeling and verification technique is presented and discussed through the aid of an example system
The Effect of Air on Granular Size Separation in a Vibrated Granular Bed
Using high-speed video and magnetic resonance imaging (MRI) we study the
motion of a large sphere in a vertically vibrated bed of smaller grains. As
previously reported we find a non-monotonic density dependence of the rise and
sink time of the large sphere. We find that this density dependence is solely
due to air drag. We investigate in detail how the motion of the intruder sphere
is influenced by size of the background particles, initial vertical position in
the bed, ambient pressure and convection. We explain our results in the
framework of a simple model and find quantitative agreement in key aspects with
numerical simulations to the model equations.Comment: 14 pages, 16 figures, submitted to PRE, corrected typos, slight
change
Efficient Compliance Checking Using BPMN-Q and Temporal Logic
Abstract. Compliance rules describe regulations, policies and quality constraints business processes must adhere to. Given the large number of rules and their frequency of change, manual compliance checking can be-come a time-consuming task. Automated compliance checking of process activities and their ordering is an alternative whenever business pro-cesses and compliance rules are described in a formal way. This paper introduces an approach for automated compliance checking. Compliance rules are translated into temporal logic formulae that serve as input to model checkers which in turn verify whether a process model satisfies the requested compliance rule. To address the problem of state-space explo-sion we employ a set of reduction rules. The approach is prototypically realized and evaluated.
Using the guard-stage-milestone notation for monitoring BPMN-based processes
Business processes are usually designed by means of imperative languages to model the acceptable execution of the activities performed within a system or an organization. At the same time, declarative languages are better suited to check the conformance of the states and transitions of the modeled process with respect to its actual execution. To avoid defining models twice from scratch to cope with both the process enactment and its monitoring, this paper proposes an approach for translating BPMN process models to E-GSM ones: an extension of the Guard-Stage-Milestone artifact-centric notation. The paper also shows how a monitoring engine based on E-GSM specifications can detect anomalies during the execution of the process and classify them according to different levels of severity, that is, with respect to the impact on the outcome of the process
Delivering strong 1H nuclear hyperpolarization levels and long magnetic lifetimes through signal amplification by reversible exchange
Hyperpolarization turns typically weak NMR and MRI responses into strong signals so that ordinarily impractical measurements become possible. The potential to revolutionize analytical NMR and clinical diagnosis through this approach reflect this area's most compelling outcomes. Methods to optimize the low cost parahydrogen based approach signal amplification by reversible exchange (SABRE) with studies on a series of biologically relevant nicotinamides and methyl nicotinates are detailed. These procedures involve specific 2H-labelling in both the agent and catalyst and achieve polarization lifetimes of ca. 2 minutes with 50% polarization in the case of 4,6-d2-methylnicotinate. As a 1.5 T hospital scanner has an effective 1H polarization level of just 0.0005% this strategy should result in compressed detection times for chemically discerning measurements that probe disease. To demonstrate this techniques generality, we exemplify further studies on a range of pyridazine, pyrimidine, pyrazine and isonicotinamide analogues that feature as building blocks in biochemistry and many disease treating drugs
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