33 research outputs found

    Logistics performance measurement system for the automotive industry

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    Logistics can be seen as a key competitive factor in the automotive industry due to the rising number of model variants and options. With the increasing importance of logistics (Gunasekaran et al. in Int J Prod Econ 87(3):333-347, 2004), the evaluation of logistics effectiveness and efficiency is gaining increased attention. Logistics performance management (PM) is the key to quantifying the current state and improvement potentials within logistics. To account for the increasing importance of a supply chain, logistics PM needs to start at the supplier and reach at least until the original equipment manufacturer's (OEM) assembly line. Furthermore, logistics PM needs to be in line with the latest logistics concepts, mainly based on lean logistics. In contrast to the great importance of logistics PM, the literature analysis shows a limited availability of logistics performance measurement systems (PMS), which are actually applicable to industry within a lean logistics context. The systems in the literature are either too high level to be useful to practitioners (e.g. supply chain-orientated systems) or too narrow in focus, and therefore do not cover the supply chain and lean perspectives. In the following paper, a logistics PMS is developed which allows for assessing the effectiveness and efficiency of current logistics processes. The developed approach incorporates the latest logistics concepts in the automotive industry, integrates a process orientation with a supply chain perspective, and is defined with the specificity required to enable the implementation within a specific industry context and triggers continuous improvement. The suggested framework is evaluated in an automotive context, presenting a short case study on the implementation of the proposed framework at two sites of a German automotive OEM. Furthermore, future application potentials and development needs are summarised. The paper's contribution to the literature is in the field of logistics PM, specifically in the automotive industry. It offers a new approach, applicable to automotive logistics, which follows lean principles. For industry, this paper provides specific suggestions for a PMS, as well as performance indicators to holistically monitor the logistics chain. While being generic in terms of its definition, it can be seen as specific enough to be applicable in industry with limited adjustments. It provides practitioners with answers to the question of which performance indicators to use in today's automotive logistics chain and which indicators serve as a base for continuous improvement

    Free-space propagation of high dimensional structured optical fields in an urban environment

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    Spatially structured optical fields have been used to enhance the functionality of a wide variety of systems that use light for sensing or information transfer. As higher-dimensional modes become a solution of choice in optical systems, it is important to develop channel models that suitably predict the effect of atmospheric turbulence on these modes. We investigate the propagation of a set of orthogonal spatial modes across a free-space channel between two buildings separated by 1.6 km. Given the circular geometry of a common optical lens, the orthogonal mode set we choose to implement is that described by the Laguerre-Gaussian (LG) field equations. Our study focuses on the preservation of phase purity, which is vital for spatial multiplexing and any system requiring full quantumstate tomography. We present experimental data for the modal degradation in a real urban environment and draw a comparison to recognized theoretical predictions of the link. Our findings indicate that adaptations to channel models are required to simulate the effects of atmospheric turbulence placed on high-dimensional structured modes that propagate over a long distance. Our study indicates that with mitigation of vortex splitting, potentially through precorrection techniques, one could overcome the challenges in a real point-to-point free-space channel in an urban environment

    Second Order Perturbations in the Randall-Sundrum Infinite Brane-World Model

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    We discuss the non-linear gravitational interactions in the Randall-Sundrum single brane model. If we naively write down the 4-dimensional effective action integrating over the fifth dimension with the aid of the decomposition with respect to eigen modes of 4-dimensional d'Alembertian, the Kaluza-Klein mode coupling seems to be ill-defined. We carefully analyze second order perturbations of the gravitational field induced on the 3-brane under the assumption of the static and axial-symmetric 5-dimensional metric. It is shown that there remains no pathological feature in the Kaluza-Klein mode coupling after the summation over all different mass modes. Furthermore, the leading Kaluza-Klein corrections are shown to be sufficiently suppressed in comparison with the leading order term which is obtained by the zero mode truncation. We confirm that the 4-dimensional Einstein gravity is approximately recovered on the 3-brane up to second order perturbations.Comment: 15 pages, 2 figures, comment and reference added, typos correcte

    Histone H3.3 beyond cancer: Germline mutations in Histone 3 Family 3A and 3B cause a previously unidentified neurodegenerative disorder in 46 patients

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    Although somatic mutations in Histone 3.3 (H3.3) are well-studied drivers of oncogenesis, the role of germline mutations remains unreported. We analyze 46 patients bearing de novo germline mutations in histone 3 family 3A (H3F3A) or H3F3B with progressive neurologic dysfunction and congenital anomalies without malignancies. Molecular modeling of all 37 variants demonstrated clear disruptions in interactions with DNA, other histones, and histone chaperone proteins. Patient histone posttranslational modifications (PTMs) analysis revealed notably aberrant local PTM patterns distinct from the somatic lysine mutations that cause global PTM dysregulation. RNA sequencing on patient cells demonstrated up-regulated gene expression related to mitosis and cell division, and cellular assays confirmed an increased proliferative capacity. A zebrafish model showed craniofacial anomalies and a defect in Foxd3-derived glia. These data suggest that the mechanism of germline mutations are distinct from cancer-associated somatic histone mutations but may converge on control of cell proliferation
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