76,177 research outputs found

    An empirical analysis of lean six sigma implementation in SMEs – A migratory perspective

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    The purpose of this paper is to investigate the migratory nature of Lean Six Sigma (LSS) implementation in manufacturing based SMEs in the UK. The companies were surveyed at two points over a five year period. These periods were before and after the 2008 recession point and were identified in order to assess the level of LSS implementation as a result of the tougher economic climate that has prevailed in the manufacturing industry since 2008. Analysis is carried out on a sample of 96 manufacturing SMEs from a range of manufacturing sectors in the UK. Data was gathered from company CEOs via a triangulated method of questionnaire, direct observation and interviews. The findings show the dynamic nature of LSS implementation in SMEs. Further work will be required to extend the LSS categorisation system to provide a wider category set that further defines the dynamical nature of LSS implementation

    Definition of ground test for Large Space Structure (LSS) control verification

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    An overview for the definition of a ground test for the verification of Large Space Structure (LSS) control is given. The definition contains information on the description of the LSS ground verification experiment, the project management scheme, the design, development, fabrication and checkout of the subsystems, the systems engineering and integration, the hardware subsystems, the software, and a summary which includes future LSS ground test plans. Upon completion of these items, NASA/Marshall Space Flight Center will have an LSS ground test facility which will provide sufficient data on dynamics and control verification of LSS so that LSS flight system operations can be reasonably ensured

    Science, Technology, Society, and Law

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    Law and regulation increasingly interact with science, technology, and medicine in contemporary society. Law and social science (LSS) analyses can therefore benefit from rigorous, nuanced social scientific accounts of the nature of scientific knowledge and practice. Over the past two decades, LSS scholars have increasingly turned for such accounts to the field known as science and technology studies (STS). This article reviews the LSS literature that draws on STS. Our discussion is divided into two primary sections. We first discuss LSS literature that draws on STS because it deals with issues in which law and science interact. We then discuss literature that draws on STS because it sees law as analogous to science as a knowledge-producing institution amenable to social science analysis. We suggest that through both of these avenues STS can encourage a newly critical view within LSS scholarship.</jats:p

    Cosmology with mirror dark matter II: Cosmic Microwave Background and Large Scale Structure

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    This is the second paper of a series devoted to the study of the cosmological implications of the existence of mirror dark matter. The parallel hidden mirror world has the same microphysics as the observable one and couples the latter only gravitationally. The primordial nucleosynthesis bounds demand that the mirror sector should have a smaller temperature T' than the ordinary one T, and by this reason its evolution can be substantially deviated from the standard cosmology. In this paper we took scalar adiabatic perturbations as the input in a flat Universe, and computed the power spectra for ordinary and mirror CMB and LSS, changing the cosmological parameters, and always comparing with the CDM case. We found differences in both the CMB and LSS power spectra, and we demonstrated that the LSS spectrum is particularly sensitive to the mirror parameters, due to the presence of both the oscillatory features of mirror baryons and the collisional mirror Silk damping. For x<0.3 the mirror baryon-photon decoupling happens before the matter-radiation equality, so that CMB and LSS power spectra in linear regime are equivalent for mirror and CDM cases. For higher x-values the LSS spectra strongly depend on the amount of mirror baryons. Finally, qualitatively comparing with the present observational limits on the CMB and LSS spectra, we show that for x<0.3 the entire dark matter could be made of mirror baryons, while in the case x>0.3 the pattern of the LSS power spectrum excludes the possibility of dark matter consisting entirely of mirror baryons, but they could present as admixture (up to 50%) to the conventional CDM.Comment: 36 pages, 19 figures; minor corrections in introduction, conclusions and references; accepted for publication in IJMP

    NASA/MSFC ground experiment for large space structure control verification

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    Marshall Space Flight Center has developed a facility in which closed loop control of Large Space Structures (LSS) can be demonstrated and verified. The main objective of the facility is to verify LSS control system techniques so that on orbit performance can be ensured. The facility consists of an LSS test article which is connected to a payload mounting system that provides control torque commands. It is attached to a base excitation system which will simulate disturbances most likely to occur for Orbiter and DOD payloads. A control computer will contain the calibration software, the reference system, the alignment procedures, the telemetry software, and the control algorithms. The total system will be suspended in such a fashion that LSS test article has the characteristics common to all LSS

    The Mass Function of Dark Halos in Superclusters and Voids

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    A modification of the Press-Schechter theory allowing for presence of a background large-scale structure (LSS) - a supercluster or a void, is proposed. The LSS is accounted as the statistical constraints in form of linear functionals of the random overdensity field. The deviation of the background density within the LSS is interpreted in a pseudo-cosmological sense. Using the constraints formalism may help us to probe non-trivial spatial statistics of haloes, e.g. edge and shape effects on boundaries of the superclusters and voids. Parameters of the constraints are connected to features of the LSS: its mean overdensity, a spatial scale and a shape, and spatial momenta of higher orders. It is shown that presence of a non-virialized LSS can lead to an observable deviation of the mass function. This effect is exploited to build a procedure to recover parameters of the background perturbation from the observationally estimated mass function.Comment: 23 pages, 6 figures; to be appeared in Astronomy Reports, 2014, Vol. 58, No. 6, pp. 386-39

    LSS reference platform control

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    The long range objective of this task is to develop basic technology in the design, mechanization, and analysis of control systems for large flexible space structures. The focus of the FY'81 platform control effort was on the pointing control problems associated with multiple independently controlled experiment packages operating simultaneously on a single platform. Particular emphasis was placed on obtaining a quantitative comparison of controller performance with and without base motion compensation

    Observational Constraints on Kinetic Gravity Braiding from the Integrated Sachs-Wolfe Effect

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    The cross-correlation between the integrated Sachs-Wolfe (ISW) effect and the large scale structure (LSS) is a powerful tool to constrain dark energy and alternative theories of gravity. In this paper, we obtain observational constraints on kinetic gravity braiding from the ISW-LSS cross-correlation. We find that the late-time ISW effect in the kinetic gravity braiding model anti-correlates with large scale structures in a wide range of parameters, which clearly demonstrates how one can distinguish modified gravity theories from the LCDM model using the ISW effect. In addition to the analysis based on a concrete model, we investigate a future prospect of the ISW-LSS cross-correlation by using a phenomenological parameterization of modified gravity models.Comment: 7 pages, 3 figures, accepted for publication in Physical Review
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