In Industry 4.0, Human Machine Interfaces are largely used in order to increase the performances of production processes at the same time reducing the number of emergencies and accidents. In manufacturing, the most typical system used to monitor the production is the Andon. It is a graphical system exploited in plants to notify operators who deal with management, maintenance and production performance of the presence of a problem. Of course, the usability of such interfaces is essential to allow an operator to identify and react more effectively to potentially critical situations. Improving the usability of such interfaces is a big challenge due to the increasing complexity of the data that must be processed and understood quickly by operators. In this paper, we present a set of guidelines to help professional developers to design usable interfaces for monitoring industrial production in manufacturing. Such guidelines are based on usability principles and formalized by reviewing existing industrial interfaces. Using a realistic case study prepared with manufacturing experts, we propose an Andon interface that we developed to test the efficacy of these guidelines on a last generation touch-wall device.

In recent years there has been a growth in size and complexity of the projects managed by public or private organizations. This leads to increased probability of project failures, frequently due to the difficulty and the ability to achieve the objectives such as on-time delivery, cost containment, expected quality achievement. In particular, one of the most common causes of project failure is the very high degree of uncertainty that affects the expected performance of the project, especially when different stakeholders with divergent aims and goals are involved in the project.

The problem of performance evaluation of business processes supported by Workflow Management Systems is a recent research issue. In this paper, we propose an approach to the performance evaluation of automated business processes based on the measurement language WPQL (Workflow Performance Query Language). The paper first describes the WPQL architecture together with a selection mechanism by means of which the workflow entities to measure are isolated. Then, the main constructs of WPQL for measure definition and measure application are presented and exemplified. Finally, we show a working session of the support tool and discuss some guideline for further research.

The problem of performance evaluation of business processes supported by Workflow Management Systems is a recent research issue. In this paper we propose a measurement framework in which several aspects concerning the timing and working of a business process, either as a whole or in terms of its components, can be precisely quantified. Our approach is based on the workflow model introduced by the Workflow Management Coalition and introduces some fundamental measures from which a number of derived measures can be hierarchically obtained. The paper describes the basic structures and the primitive operators of the framework as well as the fundamental and derived measures. Techniques for the evaluation of complex processes are also discussed. The proposed framework is quite general and can be applied to research and commercial workflow management systems with relatively little implementation effort.

The literature offers several examples of executable specification languages, ranging from mathematically based notation to visual formalisms. In this paper, an analysis environment for executable system specifications based on the language RSF (Requirement Specification Formalism) is presented. The analysis environment also contains two other linguistic tools — RSQ (Requirement Specification Querying), and SEF (Specification Execution Filtering). Using RSQ, classes of execution paths with certain properties can be exercised, so that selected behavioral aspects can be observed. Using SEF, the amount of information and the times at which it is output can be controlled, making the behavior analysis more effective. The paper shows how the notation of RSF, with its few basic concepts, is naturally exploited as a nucleus for the other tools, which are easily integrated to produce the final analysis environment. The combination of RSQ and SEF allows the planning of testing and analysis activities. A working session is shown for a specification describing a telephone switch call handler.

A system for the definition, querying and analysis of executable specification is presented in the paper. After a short review RSF, a specification language for the definition of systems with time constraints, the authors consider the problem of querying the specifications. The query language RSQ allows one to characterize sub-classes of possible specification execution behaviours in terms of queries directed to the specification. The problem of selection of significant information produced during the execution of the specification is also considered. The system proposes three linguistic tools, one for the definition, one for the querying and the last for the filtering of executable software specifications. The linguistic tools are quite homogeneous both in their syntax and semantics and support the organization of software behaviour inspection and analysis in the RSF prototyping environment.>

Refining a specification S1 means to provide another specification S2 which contains all the information given in S1 but with more detail. In this paper, we use logical implication from lower to higher levels of logic specifications to give a definition of refinement between these levels. This guarantees that any property of the higher level is also verified at the lower one. The definition of the relation "is refinement of" is given for specifications which are general first-order theories and it is proved to be transitive. A relevant aspect is that the different levels of logic specifications are in general not immediately comparable, because they can use different vocabularies. For this reason, the concept of transcription is introduced formally in our definition. Then the particular case of Horn specifications is considered. Horn specification semantics can be given by the methodology of least models. This may suggest definitions of the concept of refinement different from the one based on logical implication from lower to higher levels. However, conceptual problems can arise depending on the kind of the refinement definition chosen. Perhaps the most interesting effect is that the property of refinement transitivity may be lost. A possible way to restore the transitivity is provided.

The availability of executable specification languages allows testing to be carried out soon after or concurrently with the requirements specification phase. In addition, it becomes possible to use these languages for rapid prototyping, making it possible to gather information on properties of the specified target system including its behavior in response to external events. The inspection of software behavior is viewed as the querying of executable specifications. A language RSQ is defined for the purpose of constructing queries against executable specifications expressed in RSF, a language for the description of systems with time constraints. A query is able to single out a subclass of possible behaviors based on properties supplied by the query. The integration of RSQ with RSF enhances the analytical abilities of the software designer and developer.>