Requirements for the Design of Flexible and Changeable Manufacturing and Assembly Systems: A SME-survey☆

Abstract Increasingly complex market dynamics due to unpredictable forecasts and shorter innovation cycles require maximum flexibility from production companies and their manufacturing systems. A manufacturing system should not only produce high-quality products at the lowest possible price; it should also be able to react quickly to market changes and consumers preferences. After the implementation in large enterprises belonging to the automotive sector and other related sectors, the concept of flexibility and changeability has been introduced in small and medium-sized enterprises (SME). In recent years, the concept of flexibility and changeability was object of research and industry. Current research in manufacturing pays great attention to flexibility and changeability in manufacturing and assembly systems. Therefore, research and investigations are needed to analyze the requirements for the design of flexible and changeable manufacturing and assembly systems in SMEs in order to define simple and practically suitable design guidelines. This research analyzes the nature of environmental changes, which SMEs are currently facing, due to a questionnaire-based survey. This research paper summarizes the results of the survey, executed with 27 SME companies in North Italy, showing the main requirements for the design of flexible and changeable manufacturing and assembly systems

Correlation density matrices for 1- dimensional quantum chains based on the density matrix renormalization group

A useful concept for finding numerically the dominant correlations of a given ground state in an interacting quantum lattice system in an unbiased way is the correlation density matrix. For two disjoint, separated clusters, it is defined to be the density matrix of their union minus the direct product of their individual density matrices and contains all correlations between the two clusters. We show how to extract from the correlation density matrix a general overview of the correlations as well as detailed information on the operators carrying long-range correlations and the spatial dependence of their correlation functions. To determine the correlation density matrix, we calculate the ground state for a class of spinless extended Hubbard models using the density matrix renormalization group. This numerical method is based on matrix product states for which the correlation density matrix can be obtained straightforwardly. In an appendix, we give a detailed tutorial introduction to our variational matrix product state approach for ground state calculations for 1- dimensional quantum chain models. We show in detail how matrix product states overcome the problem of large Hilbert space dimensions in these models and describe all techniques which are needed for handling them in practice.Comment: 50 pages, 34 figures, to be published in New Journal of Physic

Stroboscopic observation of quantum many-body dynamics

Recent experiments have demonstrated single-site resolved observation of cold atoms in optical lattices. Thus, in the future it may be possible to take repeated snapshots of an interacting quantum many-body system during the course of its evolution. Here we address the impact of the resulting quantum (anti-)Zeno physics on the many-body dynamics. We use the time-dependent density-matrix renormalization group to obtain the time evolution of the full wave function, which is then periodically projected in order to simulate realizations of stroboscopic measurements. For the example of a one-dimensional lattice of spinless fermions with nearest-neighbor interactions, we find regimes for which many-particle configurations are stabilized or destabilized, depending on the interaction strength and the time between observations

Kondo screening cloud in the single-impurity Anderson model: A density matrix renormalization group study

A magnetic moment in a metal or in a quantum dot is, at low temperatures, screened by the conduction electrons through the mechanism of the Kondo effect. This gives rise to spin-spin correlations between the magnetic moment and the conduction electrons, which can have a substantial spatial extension. We study this phenomenon, the so-called Kondo cloud, by means of the density matrix renormalization group method for the case of the single-impurity Anderson model. We focus on the question whether the Kondo screening length, typically assumed to be proportional to the inverse Kondo temperature, can be extracted from the spin-spin correlations. For several mechanisms -- the gate potential and a magnetic field -- which destroy the Kondo effect, we investigate the behavior of the screening cloud induced by these perturbations.Comment: updated some data, minor change

How does grazing relate to body mass index, self-compassion, mindfulness and mindful eating in a student population?

Contemporary research investigating obesity has focused on grazing (i.e. an uncontrolled and repetitive consumption of small amounts of food). Meanwhile, constructs such as mindfulness, mindful eating and self-compassion have received much attention in assisting individuals with eating behaviours and weight regulation. The association between those constructs and grazing, however, has not been explored. In a cross-sectional study, university students ( n  = 261) were recruited to explore the relationship of mindfulness, mindful eating and self-compassion with current weight and grazing. Results indicated that all constructs were negatively related to grazing, but only mindful eating related negatively to current weight. In addition, mindful eating mediated the relationship between grazing and current weight. Possible explanations and future directions are discussed further with an emphasis on the need for more empirical work

Improvement of quality of life, anxiety and depression after surgery in patients with stress urinary incontinence: Results of a longitudinal short-term follow-up

<p>Abstract</p> <p>Objective</p> <p>The objective of this study was to compare the effect of incontinence surgery and pelvic floor training on quality of life (QOL), anxiety and depression in patients with stress urinary incontinence (SUI).</p> <p>Methods</p> <p>In a prospective longitudinal study, females with proven SUI were asked to complete a set of standardized questionnaires (sociodemographic data sheet, FACT-G, I-QOL, HADS) before and eight weeks after treatment. The comparison groups consisted of a surgical treatment group and a conservative group that underwent supervised pelvic floor training for eight weeks.</p> <p>Results</p> <p>From the 67 female patients included in the study a number of 53 patients completed both assessment time points (mean age 57.4, mean years of SUI 7.6). The surgical treatment group consisted of 32 patients of which 21 patients received a modified Burch colposuspension and 11 patients a tension-free mid-urethral tape suspension. The 21 patients in the conservative group attended eight once-weekly supervised pelvic floor training sessions.</p> <p>After treatment the surgical intervention group showed a significantly higher improvement of QOL (FACT-G and I-QOL) and anxiety (HADS) than the pelvic floor training group.</p> <p>Conclusion</p> <p>For female patients with SUI surgery yielded a better outcome than pelvic floor training with regard to quality of life and anxiety.</p