Cloud e-learning for mechatronics: CLEM

his paper describes results of the CLEM project, Cloud E-learning for Mechatronics. CLEM is an example of a domain-specific cloud that is especially tuned to the needs of VET (Vocational, Education and Training) teachers. An interesting development has been the creation of remote laboratories in the cloud. Learners can access such laboratories to support their practical learning of mechatronics without the need to set up laboratories at their own institutions. The cloud infrastructure enables multiple laboratories to come together virtually to create an ecosystem for educators and learners. From such a system, educators can pick and mix materials to create suitable courses for their students and the learners can experience different types of devices and laboratories through the cloud. The paper provides an overview of this new cloud-based e-learning approach and presents the results. The paper explains how the use of cloud computing has enabled the development of a new method, showing how a holistic e-learning experience can be obtained through use of static, dynamic and interactive material together with facilities for collaboration and innovation

Genetic basis for variation in plasma IL-18 levels in persons with chronic hepatitis C virus and human immunodeficiency virus-1 infections

Inflammasomes are multi-protein complexes integrating pathogen-triggered signaling leading to the generation of pro-inflammatory cytokines including interleukin-18 (IL-18). Hepatitis C virus (HCV) and human immunodeficiency virus (HIV) infections are associated with elevated IL-18, suggesting inflammasome activation. However, there is marked person-to-person variation in the inflammasome response to HCV and HIV. We hypothesized that host genetics may explain this variation. To test this, we analyzed the associations of plasma IL-18 levels and polymorphisms in 10 genes in the inflammasome cascade. About 1538 participants with active HIV and/or HCV infection in three ancestry groups are included. Samples were genotyped using the Illumina Omni 1-quad and Omni 2.5 arrays. Linear regression analyses were performed to test the association of variants with log IL-18 including HCV and HIV infection status, and HIV RNA in each ancestry group and then meta-analyzed. Eleven highly correlated single-nucleotide polymorphisms (r²=0.98–1) in the IL-18-BCO2 region were significantly associated with log IL-18; each T allele of rs80011693 confers a decrease of 0.06 log pg ml⁻¹ of IL-18 after adjusting for covariates (rs80011693; rs111311302 β=−0.06, P-value=2.7 × 10⁻⁴). In conclusion, genetic variation in IL-18 is associated with IL-18 production in response to HIV and HCV infection, and may explain variability in the inflammatory outcomes of chronic viral infections

Family Business Restructuring:A Review and Research Agenda

Although business restructuring occurs frequently and it is important for the prosperity of family firms across generations, research on family firms has largely evolved separately from research on business restructuring. This is a missed opportunity, since the two domains are complementary, and understanding the context, process, content, and outcome dimensions is relevant to both research streams. We address this by examining the intersection between research on business restructuring and family firms to improve our knowledge of each area and inform future research. To achieve this goal, we review and organize research across different dimensions to create an integrative framework. Building on current research, we focus on 88 studies at the intersection of family firm and business restructuring research to develop a model that identifies research needs and suggests directions for future research

DOI: 10.1016/j.irfa.2013.01.002 Ownership structure and acquirers performance: Family vs. Non-family firms

This paper investigates the impact of family control on French acquirers ’ performance. We consider a sample of 239 acquisitions undertaken by French listed companies between January 1997 and December 2006. Comparing both, short-term and long-term performance, we find that family-controlled firms outperform non-family firms. We find that the relationship depends on the control level. The higher operating performance of family firms is statistically significant for an intermediate level of control. Around the announcement date, family firms with a high level of control outperform non-family firms. Using the calendar time approach, we find that long-term stock performance of family firms is positive and statistically significant. Robustness tests show that our findings seem to not be driven by the endogeneity problem. Finally, we find that family wedge, due to the use of the pyramidal structure and the double voting rules, has no statistical significant effect

Stiffness optimization of a cable driven parallel robot for additive manufacturing

International audienceIn this paper, the optimization of the anchor points of a cable driven parallel robot (CDPR) for 3D printing is proposed in order to maximize the rigidity. Indeed, in the context of 3D printing, robot stiffness should guarantee a high level of tool path following accuracy. The optimized platform showed a rigidity improvement in simulation, but also experimentally with a first study of vibration modes. In the same time, this study illustrates the influence of preload in cables on the platform rigidity

3D visual-based tension control in strip-like deformable objects using a catenary model

International audienceIn recent years, there has been a growing interest in robotic manipulation of deformable objects. In order to perform certain tasks, the robot must control the shape of the object while taking care not to apply excessive stresses so as not to deform it irreversibly. This is the case when extracting elasto-plastic objects in strips from an industrial reel. In order to control the mechanical stresses within the object, we propose a vision-based control scheme to minimize tension by regulating the angular velocity of a motorized reel on which they are wound. In this paper, we propose a method, based on a catenary model and visual feedback from a low-cost RGB-D camera, to estimate the tension distribution along a rubber strip. Thus, the control strategy aims to achieve a desired tension value by varying the length of the suspended portion of the manipulated strip. Simulation and experimental results validate the proposed approach for strip-like objects of various dimensions

Modelling and simulation of an harvester head mechanism

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Machining performance optimization of Parallel Kinematic Machines tools with regard to their anisotropic behaviour

Today, Parallel Kinematic Machines tools (PKMs) appear in automotive and aeronautic industries. These machines allow a benefit of productivity due to their higher kinematics performances than Serial Kinematic Machines tools (SKMs). However, their machining accuracy is lower. Moreover, the compensation of the defects which penalizes the machined parts quality is difficult due to their anisotropic behaviour. Thus, this article deals with the development of methods improving the machined parts quality and the productivity. In order to improve parts quality, the static behaviour of the machine structure is considered with a model taking into account joints and legs compliances. Then, it allows determining a static workspace. About the productivity, the improvement of kinematics performances is performed through an optimization work of the non productive tool path between cutting operations. The computed tool path must verify a minimum time constraint and avoid collisions between the tool and the machined part. All the methods are illustrated with the PKM Tripteor X7 developed by PCI