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This paper aims at supporting business process designers in modelling collaborative scenarios in terms of hierarchical BPMN collaboration diagrams, to enforce consistency among different hierarchical levels.

The proposed approach is based on a set of guidelines to apply during the modelling of hierarchical diagrams. These guidelines address consistency issues related to the hiding capability provided by sub-process and call activity elements, which may obscure behaviours at inner levels, especially exchange of messages, that are inconsistent with those in other hierarchical levels. A laboratory experience validates the guidelines' effectiveness.

The paper points out the issues of hierarchical diagrams, and the lack of support in this context from the existing BPMN modelling tools. Moreover, through a laboratory experience, the paper shows the benefits carried by the proposed guidelines concerning the quality of the modelled diagrams.

The proposed guidelines have been implemented in a consistency checking tool that avoids consistency errors during the modelling activity. To foster its usage, the tool has been integrated into the Eclipse BPMN modelling environment.

The paper, employing consistency guidelines, provides a novel solution to the weaknesses of hierarchical modelling.

Public services can be modelled, analysed and implemented using notations and tools for the business process (BP) abstraction. Applying such an explicit approach public administrations (PAs) can better react to the undergoing transformation in service provisioning and they can continuously improve service quality in order to satisfy citizens and business requests, while coping with decreasing budgets. The purpose of this paper is to discuss these issues.

The proposed approach relies on using formal methods, in particular unfolding to analyse the correctness of BP. The paper also compares and selects mapping rules from semi-formal to formal modelling languages; these techniques are presented in the context of the BP Modelling Languages and Petri Net (PN).

Main aim of this paper is to raise the need for formal verification of BP governing the interactions among PAs, which more and more need to be supported by ICT mechanisms, and then are not so much tolerant to errors and imperfections in the process specification. The paper illustrates the main motivations of such a work and it introduces a verification technique of a BP using a mapping of a high-level notation (such as BPMN 2.0) to a formal notation (such as PNs) for which formal analysis techniques can be adopted. In particular the verification step is implemented using an unfolding-based technique.

The paper answers a call for further development of the body of knowledge on effective analysis of BPs, a rapidly emerging field of interest for large and ultra large scenarios, where a clear gap in literature exists. Than the paper shows that formal techniques are mature enough to be applied on real scenarios.

The purpose of this paper is to model how geometric errors of a machined surface (or manufacturing errors) are related to locators’ error, workpiece form error and machine tool volumetric error. A kinematic model is presented that puts into relationship the locator error, the workpiece form deviations and the machine tool volumetric error.

The paper presents a general and systematic approach for geometric error modelling in drilling because of the geometric errors of locators positioning, of workpiece datum surface and of machine tool. The model can be implemented in four steps: (1) calculation of the deviation in the workpiece reference frame because of deviations of locator positions; (2) evaluation of the deviation in the workpiece reference frame owing to form deviations in the datum surfaces of the workpiece; (3) formulation of the volumetric error of the machine tool; and (4) combination of those three models.

The advantage of this approach lies in that it enables the source errors affecting the drilling accuracy to be explicitly separated, thereby providing designers and/or field engineers with an informative guideline for accuracy improvement through suitable measures, i.e. component tolerancing in design, machining and so on. Two typical drilling operations are taken as examples to illustrate the generality and effectiveness of this approach.

Some source errors, such as the dynamic behaviour of the machine tool, are not taken into consideration, which will be modelled in practical applications.

The proposed kinematic model may be set by means of experimental tests, concerning the industrial specific application, to identify the values of the model parameters, such as standard deviation of the machine tool axes positioning and rotational errors. Then, it may be easily used to foresee the location deviation of a single or a pattern of holes.

The approaches present in the literature aim to model only one or at most two sources of machining error, such as fixturing, machine tool or workpiece datum. This paper goes beyond the state of the art because it considers the locator errors together with the form deviation on the datum surface into contact with the locators and, then, the volumetric error of the machine tool.

The purpose of this paper is to present a skin-based approach able to generate the variability model for a component in composite material due to its manufacturing process. It generates a skin-based model of the manufactured part. The skin model discretizes the part surfaces by points to take into account the geometric deviations, those points are the nodes of finite element analysis used for tolerance analysis of compliant assemblies.

The paper presents a general and systematic simulation model for generating a variability meta-model for a component in composite material due to its manufacturing process. The model is constituted by three steps: definition and pre-processing of the nominal model, generation of the manufacturing process model and evaluation of the part variability.

The advantage of this approach is related to the fact that it is designed as a part of a digital process that establishes a continuous and unambiguous flow of variation information from the part design to manufacturing and assembly and that takes into account the manufacturing signature. This is its uniqueness compared to other simulation approaches focused only on manufacturing.

Considering the variability around the nominal value of all the process parameters and parts with more complex geometries are not taken into account now, which will be modelled in practical applications.

To properly manage uncertainty since conceptual design of complex product, next generation geometry assurance requires simulation models to realistically consider process signatures due to the manufacturing process. This work focusses on this next generation tool for geometry assurance.

The literature is focused on metal sheets joined by welding or riveting. There are other materials widely used and typically compliant: the composite materials that typically used mechanical fixing elements (bolting, riveting) and structural adhesives to joint parts. No software tools exist in the literature to deal with uncertainty from manufacturing to assembly processes in products made by composite. This is the reason of the present work.

The purpose of this work is to present a variational model able to deal with form tolerances and assembly conditions. The variational model is one of the methods proposed in literature for tolerance analysis, but it cannot deal with form tolerances and assembly conditions that may influence the functional requirements of mechanical assemblies.

This work shows how to manage the actual surfaces generated by the manufacturing process and the operating conditions inside the variational model that has been modified to integrate the manufacturing signature left on the surfaces of the parts and the operating conditions that arise during an actual assembly, such as gravity and friction. Moreover, a geometrical model was developed to numerically simulate what happens in a real assembly process and to give a reference value.

The new variational model was applied to a three-dimensional case study. The obtained results were compared to those of the geometrical model and to those of the variational model to validate the new model and to show the improvements.

The proposed approach may be extended to other models of literature. However, its limitation is that it is able to deal with a sphere–plane contact.

Tolerance analysis is a valid tool to foresee geometric interferences among the components of an assembly before getting the physical assembly. It involves a decrease in the manufacturing costs.

The main contributions of the study are the insertion of a systematic pattern characterizing the features manufactured by a process, assembly operating conditions and development of a geometrical model to reproduce what happens in a real assembly process.

The purpose of this paper is to carry out a tolerance analysis with geometric tolerances by means of the Jacobian model. Tolerance analysis is an important task to design and to manufacture high-precision mechanical assemblies; it has received considerable attention by the literature. The Jacobian model is one of the methods proposed by the literature for tolerance analysis. The Jacobian model cannot deal with geometric tolerances for mechanical assemblies. The geometric tolerances may not be neglected for assemblies, as they significantly influence their functional requirements.

This paper presents how it is possible to deal with geometric tolerances when a tolerance analysis is carried out by means of a Jacobian model for a 2D and 3D assemblies for which the geometric tolerances applied to the components involve only translational deviations. The three proposed approaches modify the expression of the stack-up function to overcome the shortage of Jacobian model that the geometric error cannot be processed.

The proposed approach has been applied to a case study. The results of the case study show how, when a statistical approach is implemented, the Jacobian model with the three developed methods gives results very similar to those due to other models of the literature, such as vector loop and variational.

In particular, the proposed approach may be applied only when the applied geometrical tolerances involve translational variations in 3D assemblies.

Tolerance analysis is a valid tool to foresee geometric interferences among the components of an assembly before getting the physical assembly. It involves a decrease of the manufacturing costs.

The original contribution of the paper is due to three methods to make a Jacobian model able to consider form and geometric deviations.

This chapter focuses on the COVID-19 pandemic’s impact on the recognition through discourses of essentiality, of low-status workers and more specifically of care aides as an occupational group that performs society’s ‘dirty work’. The pandemic appears as a privileged moment to challenge the normative hegemony of how work is valued within society. However, public recognition through political discourse is a necessary but insufficient element in producing social change. Based on the theory of performativity, this chapter empirically probes conditions and mechanisms that enable a transition from discourse of essentiality to substantive recognition of the work performed by care aides in healthcare organizations. The authors rely on three main sources of data: scientific-scholarly works, documents from government, various associations and unions, and popular media reports published between February 2020 and 1 July 2022. While discourse of essentiality at the highest level of politics is associated with rapid policy response to value the work of care aides, it is embedded in a system structure and culture that restrains the establishment of substantive policy that recognizes the nature, complexity, and societal importance of care aide work. The chapter contributes to the literature on performativity by demonstrating the importance of the institutionalization of competing logics in contemporary health and social care systems and how it limits the effectiveness of discourse in promulgating new values and norms and engineering social change.

This paper aims to address the issue of long-term stability of services and systems depending on service-oriented architecture that has become a popular architecture in systems development and is often implemented using Web services. However, the dependency, especially on externally provided services, can impact the reliability of a system. This is often caused by the loose coupling also implying a less stringent policy for change management and notifications. Therefore, the authors characterise the types of changes that can happen in remote services and propose the concept of resilient web services (RWSs) as an example on how to upgrade existing services to better support the long-term stability of services and systems.

Having analysed several use cases where systems broke because of external dependencies not correctly maintained, the authors derived requirements for RWSs.

By means of a prototype implementation and evaluation of this solution in a case study, the feasibility of the approach was verified. Several scenarios of changes in WSs were simulated, correctly identified and responded to.

The authors propose a set of extensions to existing standards such as Web Services Description Language to improve the long-term availability of services in SOAs. A prototype implementation was developed for service monitoring and RWSs.