Asymptotic defectiveness of manufacturing plants: an estimate based on process learning curves

The paper describes a method for a preliminary estimation of asymptotic defectiveness of a manufacturing plant based on the prediction of its learning curve estimated during a p-chart setting up. The proposed approach provides process managers with the possibility of estimating the asymptotic variability of the process and the period of revision of p-chart control limits. An application of the method is also provided

FMECA methodology applied to two pathways in an orthopaedic hospital in Milan.

INTRODUCTION: Adverse events pose a challenge to medical management: they can produce mild or transient disabilities or lead to permanent disabilities or even death; preventable adverse events result from error or equipment failure. METHODS: IRCCS Istituto Ortopedico Galeazzi implemented a clinical risk management program in order to study the epidemiology of adverse events and to improve new pathways for preventing clinical errors: a risk management FMECA-FMEA pro-active analysis was applied either to an existing clinical support pathway or to a new process before its implementation. RESULTS: The application of FMEA-FMECA allowed the clinical risk unit of our hospital to undertake corrective actions in order to reduce the adverse events and errors on high-risk procedure used inside the hospitals

Nectar ecology of the endemic epiphytic hummingbird-pollinated bromeliad Vriesea altodaserrae: secretion dynamics and pollinator visitation pattern

Hummingbirds are the main pollinators of most bromeliad species, whose nectar traits usually respond to the selective pressures imposed by pollinators. Considering the specialization of hummingbird-pollinated bromeliads, we expect a close relationship between nectar ecophysiology and the needs of the main pollinators. In this sense, we studied the nectar ecology of the endemic epiphytic bromeliad Vriesea altodaserrae by assessing its nectar traits to address the following questions: i) do flowers respond to successive experimental removals of nectar? ii) is hummingbird visitation frequency related to nectar secretion pattern? We found that V. altodaserrae depended completely on hummingbirds for sexual reproduction, and nectar composition was consistent with that of most hummingbird-pollinated species. Most of the nectar was secreted at bud stage and, if not removed, flowers reabsorb it at the end of their lifespan. Total nectar production did not change after successive removals, and nectar secretion rhythm did not affect the frequency of hummingbird visits. Vriesea altodaserrae was visited by two-thirds of the hummingbird species recorded at the study site, but especially by those of Trochilinae subfamily, suggesting specialization for this group of hummingbirds and highlighting the importance this endemic bromeliad as a keystone species in areas of highland Atlantic fores

Measurement noise of a point autofocus surface topography instrument

Optical instruments for areal topography measurement can be especially sensitive to noise when scanning is required. Such noise has different sources, including those internally generated and external sources from the environment [1].For some instruments, it is not always possible to evaluate each single contributor. Nevertheless, it is possible to evaluate the noise added to the output during the normal use of the instrument. Such noise is defined in ISO 25178 part 605 [1] as “measurement noise”. In this work, the measurement noise is assessed for a commercial point autofocus instrument (Mitaka MLP-3SP), installed in the manufacturing metrology laboratory at The University of Nottingham. The investigation is carried out by areal acquisitions of 100µm×100µmwith a100×magnification objective and a sampling distance of 0.1µm along the x-axis and 1µm along the y-axis. The measurement noise is evaluated by applying established subtraction and averaging methods described elsewhere [2,3]. The results reveal a maximum calculated value of 20nm (subtraction method) and a minimum of 8nm (subtraction method). An oscillationis observed in the acquired surface topographies, which is due to a thermal drift induced by the air conditioning system. The disturbance can be reduced using the temperature correction tool in the software of the instrument. Experiments performed when the air conditioning system is inactive, showed drift of the instrument due to the temperature which is estimated, in the worst case, as 0.9µm/oC(calculated as Sz/ΔT), over one hour measuring time. The investigation was then repeated applying the temperature correction tool and the evaluation of the measurement noise results in a value of 2nm (both methods).The overall temperature variation, measured in the housing chamber of the instrument, is smaller than 0.1o C during each repeated measurement. In conclusion, the point autofocus instrument shows a clear dependence on the environmental noise. The measurement noise uncertainty contributor in the worst case is estimated to be unoise=20nmwhen the temperature correction tool Abstract submitted to the www.metprops2017.se conference is not applied [2].The use of the built-in temperature correction tool allows the measurement noise uncertainty contributor to be reduced tounoise=2nm

Measurement noise of a point autofocus surface topography instrument

Optical instruments for areal topography measurement can be especially sensitive to noise when scanning is required. Such noise has different sources, including those internally generated and external sources from the environment. For some instruments, it is not always possible to evaluate each single contributor. Nevertheless, it is possible to evaluate the noise added to the output during the normal use of the instrument. Such noise is defined in ISO 25178 part 605 as “measurement noise”. In this work, the measurement noise is assessed for a commercial point autofocus instrument (Mitaka MLP-3SP), installed in the manufacturing metrology laboratory at The University of Nottingham. The investigation is carried out by areal acquisitions of 100µm×100µm with a 100× magnification objective and a sampling distance of 0.1µm along the x-axis and 1µm along the y-axis. The measurement noise is evaluated by applying established subtraction and averaging methods described elsewhere. The results reveal a maximum calculated value of 20nm (subtraction method) and a minimum of 8nm (subtraction method). An oscillationis observed in the acquired surface topographies, which is due to a thermal drift induced by the air conditioning system. The disturbance can be reduced using the temperature correction tool in the software of the instrument. Experiments performed when the air conditioning system is inactive, showed drift of the instrument due to the temperature which is estimated, in the worst case, as 0.9µm/°C (calculated as Sz/ΔT), over one hour measuring time. The investigation was then repeated applying the temperature correction tool and the evaluation of the measurement noise results in a value of 2nm (both methods).The overall temperature variation, measured in the housing chamber of the instrument, is smaller than 0.1°C during each repeated measurement. In conclusion, the point autofocus instrument shows a clear dependence on the environmental noise. The measurement noise uncertainty contributor in the worst case is estimated to be unoise=20nm when the temperature correction tool is not applied. The use of the built-in temperature correction tool allow temperature correction tool allows the measurement noise uncertainty contributor to be reduced to unoise=2 nm

Design and analysis of fractional factorial experiments from the viewpoint of computational algebraic statistics

We give an expository review of applications of computational algebraic statistics to design and analysis of fractional factorial experiments based on our recent works. For the purpose of design, the techniques of Gr\"obner bases and indicator functions allow us to treat fractional factorial designs without distinction between regular designs and non-regular designs. For the purpose of analysis of data from fractional factorial designs, the techniques of Markov bases allow us to handle discrete observations. Thus the approach of computational algebraic statistics greatly enlarges the scope of fractional factorial designs.Comment: 16 page