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The objective of this work is to find out optimum settings for a fractional PI λ controller in order to fulfill three different robustness specifications of design for the compensated system, taking advantage of the fractional order, λ. Since this fractional controller has one parameter more than the conventional PI controller, one more specification can be fulfilled, improving the performance of the system and making it more robust to plant uncertainties, such as gain and time constant changes. For the tuning of the controller an iterative optimization method has been used, based on a nonlinear function minimization. Two real examples of application are presented and simulation results are shown to illustrate the effectiveness of this kind of unconventional controllers.

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The article provides a conceptualisation of the link between recent migration flows and labour market uncertainty through the analysis of a critical example, the construction sector (characterised by economic volatility, worker mobility, employment insecurity, safety risk) in the UK and Spain (countries with large immigration, flexible labour markets and volatile construction sectors). Transnational labour mobility can be seen as a structural response to recent European dilemmas on how to combine flexibility and security, through the creation of a hyper-flexible buffer of migrant workers who, being disposable in case of downturn, can carry most of the uncertainty burden without causing political problems. This raises two issues: the social sustainability of such segmentation, in particular with regard to occupational health and safety, and the role organised labour can have on it, in particular in organising such workers. The issues are analysed through labour market statistics and interviews with unionists, migrant organisation representatives, employers and employment policy officers in both countries.

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In recent years the increasing amount of work related to the application of Fractional Calculus (FC) is remarkable in many areas of science and engineering. In relation to automatic control, the use of Fractional Order Control (FOC) needs, for real applications, to develop methods for controller design and parameter tuning, and efficient strategies for controller implementation. On the other hand, the Proportional Integral Derivative (PID) controller is currently by far the most widely used form of feedback controller in industrial applications. This paper, after an introduction to FC and FOC, briefly presents methods for fractional PID controller tuning, including auto-tuning, and some software and hardware strategies for efficient implementations of controllers in industrial applications.

Extensive digitization and interconnection through networks have ushered in a number of new paradigms over the last years: Internet of Things, cyber–physical systems, Industry 4.0, etc. These challenging systems rely on an effective information communication between distributed components. Therefore, the heterogeneity of entities, both hardware and software, must be handled to achieve an operative interoperability and a proper behavior. However, there is also a heterogeneous availability of solutions; different technologies, protocols, and architectures aim to achieve a seamless interconnection. Henceforth, the standardization still requires great efforts from industrial and scientific environments. In this sense, the interface of the open platform communications (OPC) has supported connectivity for automation and supervision infrastructures for more than two decades. The OPC comprises the so-called classic OPC, the original protocol, as well as the last specification, unified architecture (UA). The widespread utilization of the classic OPC together with the powerful functionalities of OPC UA, make the latter one of the main candidates to lead the standardization and systems integration. This paper presents a survey of recent OPC-based systems reported in scientific literature for different domains as well as research projects. The goal of this paper is to provide a broad perspective about the OPC’ applicability and capabilities in order to support the decision about communication interfaces. The results are analyzed and discussed putting special attention on the aforementioned new paradigms. Finally, the main conclusions and open research directions are highlighted.

We give a complete algebraic classification of nilpotent binary Lie algebras of dimension at most 6 over an arbitrary base field of characteristic not 2 and a complete geometric classification of nilpotent binary Lie algebras of dimension 6 over C. As an application, we give an algebraic and geometric classification of nilpotent anticommutative CD-algebras of dimension at most 6.Proof. Let θ ∈ Z 2 BL (A, F). Then A θ is a binary Lie algebra. We denote the Jacobian of elements x, y, z in A θ by J A θ (x, y, z). Now consider x, y, z, t ∈ A. (1.3), By the identityt] , x, y) = 0; J([x, y] , z, t) + J([x, t] , z, y) + J([z, y] , x, t) + J([z, t] , x, y) = 0; we deduce that ψ θ ([x, y] , z, t) + ψ θ ([x, t] , z, y) + ψ θ ([z, y] , x, t) + ψ θ ([z, t] , x, y) = 0, as desired.