36 resultados para Six Sigmas DMAIC


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Purpose – The Six Sigma approach to business improvement has emerged as a phenomenon in both the practitioner and academic literature with potential for achieving increased competitiveness and contributing. However, there is a lack of critical reviews covering both theory and practice. Therefore, the purpose of this paper is to critically review the literature of Six Sigma using a consistent theoretical perspective, namely absorptive capacity.

Design/methodology/approach – The literature from peer-reviewed journals has been critically reviewed using the absorptive capacity framework and dimensions of acquisition, assimilation, transformation, and exploitation.

Findings – There is evidence of emerging theoretical underpinning in relation to Six Sigma borrowing from an eclectic range of organisational theories. However, this theoretical development lags behind practice in the area. The development of Six Sigma in practice is expanding mainly through more rigorous studies and applications in service-based environments (profit and not for profit). The absorptive capacity framework is found to be a useful overarching framework within which to situate existing theoretical and practice studies.

Research limitations/implications – Agendas for further research from the critical review, in relation to both theory and practice, have been established in relation to each dimension of the absorptive capacity framework.

Practical implications – The paper shows that Six Sigma is both a strategic and operational issue and that focussing solely on define, measure, analyse, improve control-based projects can limit the strategic effectiveness of the approach within organisations.

Originality/value – Despite the increasing volume of Six Sigma literature and organisational applications, there is a paucity of critical reviews which cover both theory and practice and which suggest research agendas derived from such reviews.

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This paper uses a unique Portuguese dataset to examine the effect of access to unemployment benefits (UBs) and their maximum potential duration on escape rates from unemployment. In examining the time profile of transitions out of unemployment, the principal contributions of the paper are twofold. First, it provides a detailed state space of potential outcomes: open-ended employment, fixed-term contracts, part-time work, government-provided jobs, self employment, and labour force withdrawal. Second, it is able to exploit major exogenous discontinuities in the maximum duration of unemployment benefits to identify disincentive effects. While confirming strong disincentive effects, it is shown that use of an aggregate hazard function regression model compounds very different and even contradictory effects of the determinants of unemployment.

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Context. Several competing scenarios for planetary-system formation and evolution seek to explain how hot Jupiters came to be so close to their parent stars. Most planetary parameters evolve with time, making it hard to distinguish between models. The obliquity of an orbit with respect to the stellar rotation axis is thought to be more stable than other parameters such as eccentricity. Most planets, to date, appear aligned with the stellar rotation axis; the few misaligned planets so far detected are massive (> 2 MJ). Aims: Our goal is to measure the degree of alignment between planetary orbits and stellar spin axes, to search for potential correlations with eccentricity or other planetary parameters and to measure long term radial velocity variability indicating the presence of other bodies in the system. Methods: For transiting planets, the Rossiter-McLaughlin effect allows the measurement of the sky-projected angle ß between the stellar rotation axis and a planet's orbital axis. Using the HARPS spectrograph, we observed the Rossiter-McLaughlin effect for six transiting hot Jupiters found by the WASP consortium. We combine these with long term radial velocity measurements obtained with CORALIE. We used a combined analysis of photometry and radial velocities, fitting model parameters with the Markov Chain Monte Carlo method. After obtaining ß we attempt to statistically determine the distribution of the real spin-orbit angle ?. Results: We found that three of our targets have ß above 90°: WASP-2b: ß = 153°+11-15, WASP-15b: ß = 139.6°+5.2-4.3 and WASP-17b: ß = 148.5°+5.1-4.2; the other three (WASP-4b, WASP-5b and WASP-18b) have angles compatible with 0°. We find no dependence between the misaligned angle and planet mass nor with any other planetary parameter. All six orbits are close to circular, with only one firm detection of eccentricity e = 0.00848+0.00085-0.00095 in WASP-18b. No long-term radial acceleration was detected for any of the targets. Combining all previous 20 measurements of ß and our six and transforming them into a distribution of ? we find that between about 45 and 85% of hot Jupiters have ? > 30°. Conclusions: Most hot Jupiters are misaligned, with a large variety of spin-orbit angles. We find observations and predictions using the Kozai mechanism match well. If these observational facts are confirmed in the future, we may then conclude that most hot Jupiters are formed from a dynamical and tidal origin without the necessity to use type I or II migration. At present, standard disc migration cannot explain the observations without invoking at least another additional process.

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The aim of the Agreement and devolution in Northern Ireland is to draw together atavistic political groups in order to promote a consociational accord which upholds minority rights and cultural demands. However, it is important to understand that disagreements between the pro-British and pro-Irish populations remain and that devolution has a multiplicity of political and cultural meanings. Indeed, determining the incapacity of Northern Irish society to shift towards pluralist and less culturally subjective categorizations of belonging and political devotion remains crucially importance. This article argues that devolution is a first, although as yet unclear, step toward a range of future constitutional changes.

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The primary aim of this article is to critically analyse the development of Six Sigma theory and practice within small and medium-sized enterprises (SMEs) using a multiple case study approach. The article also explores the subsequent development of Lean Six Sigma as a means of addressing the perceived limitations of the efficacy of Six Sigma in this context. The overarching theoretical framework is that of absorptive capacity, where Six Sigma is conceptualized as new knowledge to be absorbed by smaller firms. The findings from a multiple case study involving repeat interviews and focus groups informed the development of an analytical model demonstrating the dynamic underlying routines for the absorptive capacity process and the development of a number of summative propositions relating the characteristics of SMEs to Six Sigma and Lean Six Sigma implementation.

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The search for the progenitors of six core-collapse supernovae (CCSNe) in archival Hubble Space Telescope (HST) WFPC2 pre-explosion imaging is presented. These SNe are 1999an, 1999br, 1999ev, 2000ds, 2000ew and 2001B. Post-explosion imaging of the SNe, with the HST ACS/WFC, has been utilized with the technique of differential astrometry to identify the progenitor locations on the pre-explosion imaging. SNe 1999br, 1999ev, 2000ew and 2001B are recovered in late-time imaging, and estimates of the progenitor locations on the pre-explosion imaging, with subpixel accuracy, have been made. Only the progenitor of the Type II-P SN 1999ev has been recovered, on pre-explosion F555W imaging, at a 4.8 sigma significance level. Assuming a red supergiant progenitor, the pre-explosion observation is consistent with M-ZAMS = 15-18 M-circle dot. The progenitors of the other five SNe were below the 3 sigma detection threshold of the pre-explosion observations. The detection thresholds were translated to mass limits for the progenitors by comparison with stellar evolution models. Pre-explosion observations of the peculiarly faint SN 1999br limit the mass of a red supergiant progenitor to M-ZAMS

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The current study investigated the time-averaged velocity and turbulence intensity at the initial downstream flow from a six-bladed ship propeller. The six-bladed propeller provided the rapid periodical pulses of thrust in one revolution due to the blades leading to a complex downstream jet. The six-bladed propeller is popular as a boat racing propeller, but the presentation of its flow structure was rarely found in the previous studies. In this study, the experiments were carried out in a water tank to measure the time-averaged velocity and turbulence intensity by using a Laser Doppler Anemometry (LDA) system. The jet was produced by rotating the propeller at a constant speed powered by an electric motor. The maximum tangential and radial velocities of the six-bladed propeller were of 76% and 17% of the maximum axial velocity respectively. The study found that the six-bladed propeller has a lower tangential velocity, but a higher radial velocity with its own diffusing mechanism when comparing to the three-bladed propeller.

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Coccidiostats are the only veterinary drugs still permitted to be used as feed additives to treat poultry for coccidiosis. To protect consumers, maximum levels for their presence in food and feed have been set by the European Union (EU). To monitor these coccidiostats, a rapid and inexpensive screening method would be a useful tool. The development of such a screening method, using a flow cytometry-based immunoassay, is described. The assay uses five sets of colour-coded paramagnetic microspheres for the detection of six selected priority coccidiostats. Different coccidiostats, with and without carrier proteins, were covalently coupled onto different bead sets and tested in combination with polyclonal antisera and with a fluorescent-labelled secondary antibody. The five optimal combinations were selected for this multiplex and a simple-to-use sample extraction method was applied for screening blank and spiked eggs and feed samples. A very good correlation (r ranging from 0.995 to 0.999) was obtained with the responses obtained in two different flow cytometers (Luminex 100 and FLEXMAP 3D). The sensitivities obtained were in accordance with the levels set by the EU as the measured limits of detection for narasin/salinomycin, lasalocid, diclazuril, nicarbazin (4,4'-dinitrocarbanilide) and monensin in eggs were 0.01, 0.1, 0.5, 53 and 0.1 µg/kg and in feed 0.1, 0.2, 0.3, 9 and 1.5 µg/kg, respectively.