Policy enforcement and verification with Timed Modeling Spider Diagrams

Abstract

Abstract-Timed Modelling Spider Diagrams (TMSDs) are a visual language which supports the modeling of object-oriented systems with time constraints. They are used to define policies in which TMSDs specify admissible evolutions of the state of some instance. We define a process for deriving a rewriting system from a policy specification, so that the generated system defines a language of sequences of basic TMSDs satisfying the policy. Moreover, by identifying the different ways in which the constraints set by the policy can be violated, we can produce special rules whose application results in erroneous sequences. The resulting transformation systems can be used both to simulate possible behaviours when reasoning on the definition of policies and to test policy verification algorithms.

Resource-aware policies

“…Parking places are considered as non-shareable resources and we constrain each car to use only one parking place at a time, as per the two forbidden graphs in Figure 11. As discussed in [2], rules can be derived from a policy Π to model the transformations which bring to the creation of stories conformant to Π. Basically, one creates two types of rules: (1) for each graph G i in GSEQ and for each spider sp in SP (G i ) a set of rules to allow a spider of type tpT N m(sp) to alternate its habitat between all states inhabited by sp, and (2) for each morphism m i : G i → G i+1 in M SEQ and for each spider sp in SP (G i ), a set of rules to allow a spider of type tpT N m(sp) to transition from any of the states sp inhabits in G i to each of the states that m i (sp) inhabits in G i+1 .…”

“…We use, as running examples, a number of scenarios derived from actual parking policies, along the lines of the examples that we have used as testbed for our definition of policies [1,2] and which permit a number of variations.…”

“…System evolution is modelled through transformation rules ensuring conformity with a policy. Rules can be derived from the policy specification following a procedure described in [2].…”

A normal form for spider diagrams of order

“…It is not in Venn form as the zone ðfP; Q g; fgÞ is missing. Furthermore, the contour R is not present in d 1 and the diagram contains a spider with more than one foot. Our strategy is to first add all the missing contours to d 1 .…”

“…Due to the real-world application there has been recent interest in incorporating temporal semantics in these diagrammatic logics [1,14]. In this paper we address the problem of adding temporal semantics to Euler diagrams by adding a syntax and semantics for specifying order of the elements.…”