194,363 research outputs found

    Identifying smart design attributes for Industry 4.0 customization using a clustering Genetic Algorithm

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    Industry 4.0 aims at achieving mass customization at a mass production cost. A key component to realizing this is accurate prediction of customer needs and wants, which is however a challenging issue due to the lack of smart analytics tools. This paper investigates this issue in depth and then develops a predictive analytic framework for integrating cloud computing, big data analysis, business informatics, communication technologies, and digital industrial production systems. Computational intelligence in the form of a cluster k-means approach is used to manage relevant big data for feeding potential customer needs and wants to smart designs for targeted productivity and customized mass production. The identification of patterns from big data is achieved with cluster k-means and with the selection of optimal attributes using genetic algorithms. A car customization case study shows how it may be applied and where to assign new clusters with growing knowledge of customer needs and wants. This approach offer a number of features suitable to smart design in realizing Industry 4.0

    Robust Control Synthesis for Gust Load Alleviation from Large Aeroelastic Models with Relaxation of Spatial Discretisation

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    This paper introduces a methodology for the design of gust load control systems directly from large aeroelastic models with relaxation of spatial discretisation. A convenient state-space representation of the vortex-panel unsteady aerodynamics suitable for control synthesis is presented. This allows a full understanding of the dynamics of the linearized vortex aeroelastic model and is suitable for control system design. Through the use of robust controllers, large reductions in loading could be achieved. Comparisons are also made between robust and classical control methods. It further demonstrates that controllers synthesized from models of coarse spatial discretizations and of an order of magnitude smaller in size were capable of rejecting disturbances on fully converged models, with performances comparable to expensive higher order controllers developed from full models

    A guide for performing system safety analysis

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    A general guide is presented for performing system safety analyses of hardware, software, operations and human elements of an aerospace program. The guide describes a progression of activities that can be effectively applied to identify hazards to personnel and equipment during all periods of system development. The general process of performing safety analyses is described; setting forth in a logical order the information and data requirements, the analytical steps, and the results. These analyses are the technical basis of a system safety program. Although the guidance established by this document cannot replace human experience and judgement, it does provide a methodical approach to the identification of hazards and evaluation of risks to the system

    Statistical Delay Bound for WirelessHART Networks

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    In this paper we provide a performance analysis framework for wireless industrial networks by deriving a service curve and a bound on the delay violation probability. For this purpose we use the (min,x) stochastic network calculus as well as a recently presented recursive formula for an end-to-end delay bound of wireless heterogeneous networks. The derived results are mapped to WirelessHART networks used in process automation and were validated via simulations. In addition to WirelessHART, our results can be applied to any wireless network whose physical layer conforms the IEEE 802.15.4 standard, while its MAC protocol incorporates TDMA and channel hopping, like e.g. ISA100.11a or TSCH-based networks. The provided delay analysis is especially useful during the network design phase, offering further research potential towards optimal routing and power management in QoS-constrained wireless industrial networks.Comment: Accepted at PE-WASUN 201

    On Hirth Ring Couplings: Design Principles Including the Effect of Friction

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    Rings with Hirth couplings are primarily used for the accurate positioning of axial-symmetric components in the machine tool industry and, generally, in mechanical components. It is also possible to use Hirth rings as connection tools. Specific industries with special milling and grinding machines are able to manufacture both tailor made and standard Hirth rings available on stock. Unfortunately, no international standard (for instance ISO, DIN or AGMA) is available for the production and the design of such components. In the best-case scenario, it is possible to find simplified design formulae in the catalogue of the suppliers. The aim of this work is to provide some accurate formulae and computational methods for design to provide better awareness on the limitations and the potential of this type of connection. The work consists of five parts: (i) a review of the base calculation derived mainly from the catalogues of manufacturers; (ii) an improved calculation based on a new analytical method including the friction phenomenon; (iii) an experimentation run for validating the method; (iv) a case study applied to a machine tool; and, (v) a closed form formulation to determine an upper threshold for friction, thus ensuring the Hirth coupling regular performance

    Productive Government Expenditure and Economic Growth

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    We provide a comprehensive survey of the recent literature on the link between productive government expenditure and economic growth. Starting with the seminal paper of Robert Barro (1990) we show that an understanding of the core results of the ensuing contributions can be gained from the study of their respective Euler equations. We argue that the existing literature incorporates many relevant aspects, however, policy recommendations tend to hinge on several knife-edge assumptions. Therefore, future research ought to focus more on idea-based endogenous growth models to check the robustness of policy recommendations. Moreover, the inclusion of hitherto unexplored types of government expenditure, e. g., on the “rule of law”, would be desirable.economic growth, government expenditure, public goods, fiscal policy

    Productive Government Expenditure and Economic Growth

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    We provide a comprehensive survey of the recent literature on the link between productive government expenditure and economic growth. Starting with the seminal paper of Robert Barro (1990) we show that an understanding of the core results of the ensuing contributions can be gained from the study of their respective Euler equations. We argue that the existing literature incorporates many relevant aspects, however, policy recommen- dations tend to hinge on several knife-edge assumptions. Therefore, future research ought to focus more on idea-based endogenous growth models to check the robustness of policy recommendations. Moreover, the inclusion of hitherto unexplored types of government expenditure, e. g., on the "rule of law", would be desirable.Economic Growth, Government Expenditure, Public Goods, Fiscal Policy
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