1,720,983 research outputs found
Runtime enforcement of first-order LTL properties on data-aware business processes
No full textThis paper studies the following problem: given a relational data schema, a temporal property over the schema, and a process that modifies the data instances, how can we enforce the property during each step of the process execution? Temporal properties are defined using a first-order future time LTL (FO-LTL) and they are evaluated under finite and fixed domain assumptions. Under such restrictions, existing techniques for monitoring propositional formulas can be used, but they would require exponential space in the size of the domain. Our approach is based on the construction of a first-order automaton that is able to perform the monitoring incrementally and by using exponential space in the size of the property. Technically, we show that our mechanism captures the semantics of FO-LTL on finite but progressing sequences of instances, and it reports satisfaction or dissatisfaction of the property at the earliest possible time. © 2013 Springer-Verlag
Verification of artifact-centric systems: Decidability and modeling issues
No full textArtifact-centric business processes have recently emerged as an approach in which processes are centred around the evolution of business entities, called artifacts, giving equal importance to control-flow and data. The recent Guard-State-Milestone (GSM) framework provides means for specifying business artifacts lifecycles in a declarative manner, using constructs that match how executive-level stakeholders think about their business. However, it turns out that formal verification of GSM is undecidable even for very simple propositional temporal properties. We attack this challenging problem by translating GSM into a well-studied formal framework.We exploit this translation to isolate an interesting class of "state-bounded" GSM models for which verification of sophisticated temporal properties is decidable. We then introduce some guidelines to turn an arbitrary GSM model into a state-bounded, verifiable model. © 2013 Springer-Verlag
Composition of partially observable services exporting their behaviour
No full textIn this paper we look at the problem of composing services that export their behavior in terms of a transition system, characterizing the choices of actions given to a client at each point in time. The composition consists of synthesizing an orchestrator that coordinates the available services so as to mimic the desired target service asked by the client. Specifically, in this paper we study the "conformant form" of the problem, where available services are partially controllable and partially observable, and hence, the orchestrator has to make its decisions exploiting the observations made so far only. We give a sound and complete procedure to synthesize the orchestrator in such case, and characterize the computational complexity of the problem. The procedure is based on working with belief (or knowledge) states, a standard technique to tackle conformant planning. Moreover we show that, although in general unavoidable, the powerset construction at the base of the belief state approach can be delegated to the symbolic manipulations of the game-structure model checking tool (TLV), which can be used to efficiently implement the orchestrator synthesis procedure. Copyright © 2009, Association for the Advancement of Artificial Intelligence. All rights reserved
A Declarative Framework for Specifying and Enforcing Purpose-Aware Policies
No full textPurpose is crucial for privacy protection as it makes users confident that their personal data are processed as intended. Available proposals for the specification and enforcement of purpose-aware policies are unsatisfactory for their ambiguous semantics of purposes and/or lack of support to the run-time enforcement of policies.
In this paper, we propose a declarative framework based on a first-order temporal logic that allows us to give a precise semantics to purpose-aware policies and to reuse algorithms for the design of a run-time monitor enforcing purpose-aware policies. We also show the complexity of the generation and use of the monitor which, to the best of our knowledge, is the first such a result in literature on purpose-aware policies
Enhancing Workflow-Nets with Data for Trace Completion
No full textThe growing adoption of IT-systems for modeling and executing (business) processes or services has thrust the scientific investigation towards techniques and tools which support more complex forms of process analysis. Many of them, such as conformance checking, process alignment, mining and enhancement, rely on complete observation of past (tracked and logged) executions. In many real cases, however, the lack of human or IT-support on all the steps of process execution, as well as information hiding and abstraction of model and data, result in incomplete log information of both data and activities. This paper tackles the issue of automatically repairing traces with missing information by notably considering not only activities but also data manipulated by them. Our technique recasts such a problem in a reachability problem and provides an encoding in an action language which allows to virtually use any state-of-the-art planning to return solutions
Solving reachability problems on data-aware workflows
No full textRecent advances in the field of Business Process Management (BPM) have brought about several suites able to model data objects along with the traditional control flow perspective. Nonetheless, when it comes to formal verification there is still a lack of effective verification tools on imperative data-aware process models and executions: the data perspective is often abstracted away and verification tools are often missing.
Automated Planning is one of the core areas of Artificial Intelligence where theoretical investigations and concrete and robust tools have made possible the reasoning about dynamic systems and domains. Moreover planning techniques are gaining popularity in the context of BPM. Starting from these observations, we provide here a concrete framework for formal verification of reachability properties on an expressive, yet empirically tractable class of data-aware process models, an extension of Workflow Nets. Then we provide a rigorous mapping between the semantics of such models and that of three important Automated Planning paradigms: Action Languages, Classical Planning, and Model-Checking. Finally, we perform a comprehensive assessment of the performance of three popular tools supporting the above paradigms in solving reachability problems for imperative data-aware business processes, which paves the way for a theoretically well founded and practically viable exploitation of planning-based techniques on data-aware business processes
Smart home planning programs
No full textIn pervasive (ubiquitous) computing an increasing amount of devices are embedded and interconnected in the user's environment, e.g., a smart house. The system needs to adapt to the user's varying contexts and goals. The aim is to provide transparent services, reacting to input from the users and to the state of the environment. As user's requirements increase and new devices are inserted, new services need to be dynamically created. We present a technique that allows the user to express planning programs (i.e., procedures allowing to go through different states of the environment) and to have it realized through automatic service composition techniques. ©2010 IEEE
Conjunctive artifact-centric services
Get PDFArtifact-centric services are stateful service descriptions centered around "business artifacts", which contain both a data schema holding all the data of interest for the service, and a lifecycle schema, which specifies the process that the service enacts. In this paper, the data schemas are full-fledged relational databases, and the lifecycle schemas are specified as sets of condition-action rules, where conditions are evaluated against the current snapshot of the artifact, and where actions are suitable updates to database. The main characteristic of this work is that conditions and actions are based on conjunctive queries. In particular, we exploit recent results in data exchange to specify through tuple-generating-dependencies (tgds) the effects of actions. Using such basis we develop sound and complete verification procedures, which, in spite of the fact that the number of states of an artifact-centric service can be infinite, reduce to the finite case through a suitable use of homomorphism induced by the conjunctive queries. © 2010 Springer-Verlag
Compliance in Business Processes with Incomplete Information and Time Constraints: a General Framework based on Abductive Reasoning
Get PDFThe capability to store data about Business Process (BP) executions in so-called Event Logs has brought to the identification of a range of key reasoning services (consistency, compliance, runtime monitoring, prediction) for the analysis of process executions and process models. Tools for the provision of these services typically focus on one form of reasoning alone. Moreover, they are often very rigid in dealing with forms of incomplete information about the process execution. While this enables the development of ad hoc solutions, it also poses an obstacle for the adoption of reasoning-based solutions in the BP community. In this paper, we introduce the notion of Structured Processes with Observability and Time (SPOT models), able to support incompleteness (of traces and logs), and temporal constraints on the activity duration and between activities. Then, we exploit the power of abduction to provide a flexible, yet computationally effective framework able to reinterpret key reasoning services in terms of incompleteness and observability in a uniform way
Verification of conjunctive-query based semantic artifacts?
No full textWe introduce semantic artifacts, which are a mechanism that provides both a semantically rich representation of the information on the domain of interest in terms of an ontology, including the underlying data, and a set of actions to change such information over time. In this paper, the ontology is specified as a DL-Lite TBox together with an ABox that may contain both (known) constants and unknown individuals (labeled nulls, represented as Skolem terms). Actions are specified as sets of conditional effects, where conditions are based on conjunctive queries over the ontology (TBox and ABox), and effects are expressed in terms of new ABoxes. In this setting, which is obviously not finite state, we address the verification of temporal/dynamic properties expressed in ?-calculus. Notably, we show decidability of verification, under a suitable restriction inspired by the notion of acyclicity in data exchange
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