97 research outputs found
Enablers and Constraints in Implementing Lean Manufacturing: evidence from Brazilian SMEs
Lean Manufacturing has revolutionized the global manufacturing environment at an unprecedented rate. In scholarly and managerial literature, many works have reported that Lean Manufacturing is a very efficient approach and a straightforward way towards process improvements, in terms of productivity and value adding activities ratio. However, many studies on Lean Manufacturing have highlighted many problems in its implementation. The analysis carried out within the research project is aimed to the factors enabling or constraining the Lean Transformation of a firmâs production system, along with the most relevant tools or practices to be applied. The research methodology used is the so-called âNormative Delphiâ with a panel formed by 32 experts coming from 16 Brazilian SMEs. Our results are partially consistent with what has already been discussed in the literature and we found that the most relevant tools/practices are: value stream mapping, 5S methodology, and Kaizen (Gemba walks); the top three enabling factors are: knowledge and sponsorship of senior management, focus on continuous improvement, and employee development fostered by the company; finally, the main critical constraints are: little support from the top management, resistance to change by middle management, and poor or non-qualified Lean training activities
Epidemic mitigation by statistical inference from contact tracing data
Contact-tracing is an essential tool in order to mitigate the impact of
pandemic such as the COVID-19. In order to achieve efficient and scalable
contact-tracing in real time, digital devices can play an important role. While
a lot of attention has been paid to analyzing the privacy and ethical risks of
the associated mobile applications, so far much less research has been devoted
to optimizing their performance and assessing their impact on the mitigation of
the epidemic. We develop Bayesian inference methods to estimate the risk that
an individual is infected. This inference is based on the list of his recent
contacts and their own risk levels, as well as personal information such as
results of tests or presence of syndromes. We propose to use probabilistic risk
estimation in order to optimize testing and quarantining strategies for the
control of an epidemic. Our results show that in some range of epidemic
spreading (typically when the manual tracing of all contacts of infected people
becomes practically impossible, but before the fraction of infected people
reaches the scale where a lock-down becomes unavoidable), this inference of
individuals at risk could be an efficient way to mitigate the epidemic. Our
approaches translate into fully distributed algorithms that only require
communication between individuals who have recently been in contact. Such
communication may be encrypted and anonymized and thus compatible with privacy
preserving standards. We conclude that probabilistic risk estimation is capable
to enhance performance of digital contact tracing and should be considered in
the currently developed mobile applications.Comment: 21 pages, 7 figure
Absorbing customer knowledge: how customer involvement enables service design success
Customers are a knowledge resource outside of the firm that can be utilized for new service success by involving them in the design process. However, existing research on the impact of customer involvement (CI) is inconclusive. Knowledge about customersâ needs and on how best to serve these needs (articulated in the service concept) is best obtained from customers themselves. However, codesign runs the risk of losing control of the service concept. This research argues that of the processes of external knowledge, acquisition (via CI), customer knowledge assimilation, and concept transformation form a capability that enables the firm to exploit customer knowledge in the form of a successful new service. Data from a survey of 126 new service projects show that the impact of CI on new service success is fully mediated by customer knowledge assimilation (the deep understanding of customersâ latent needs) and concept transformation (the modification of the service concept due to customer insights). However, its impact is more nuanced. CI exhibits an ââ©â-shaped relationship with transformation, indicating there is a limit to the beneficial effect of CI. Its relationship with assimilation is âUâ shaped, suggesting a problem with cognitive inertia where initial learnings are ignored. Customer knowledge assimilation directly impacts success, while concept transformation only helps success in the presence of resource slack. An evolving new service design is only beneficial if the firm has the flexibility to adapt to change
The GAPS Programme with HARPS-N at TNG. XII. Characterization of the planetary system around HD 108874
In order to understand the observed physical and orbital diversity of extrasolar planetary systems, a full investigation of these objects and of their host stars is necessary. Within this field, one of the main purposes of the GAPS observing project with HARPS-N at TNG is to provide a more detailed characterization of already known systems. In this framework we monitored the star, hosting two giant planets, HD 108874, with HARPS-N for three years in order to refine the orbits, to improve the dynamical study and to search for additional low-mass planets in close orbits. We subtracted the radial velocity (RV) signal due to the known outer planets, finding a clear modulation of 40.2 d period. We analysed the correlation between RV residuals and the activity indicators and modelled the magnetic activity with a dedicated code. Our analysis suggests that the 40.2 d periodicity is a signature of the rotation period of the star. A refined orbital solution is provided, revealing that the system is close to a mean motion resonance of about 9:2, in a stable configuration over 1 Gyr. Stable orbits for low-mass planets are limited to regions very close to the star or far from it. Our data exclude super-Earths with Msini âł 5Mâ within 0.4 AU and objects with Msini âł 2Mâ with orbital periods of a few days. Finally we put constraints on the habitable zone of the system, assuming the presence of an exomoon orbiting the inner giant planet. Based on observations made with the Italian Telescopio Nazionale Galileo (TNG) operated on the island of La Palma by the FundaciĂłn Galileo Galilei of the INAF at the Spanish Observatorio del Roque de los Muchachos of the IAC in the frame of the programme Global Architecture of Planetary Systems (GAPS).Table A.1 is also available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/599/A90</A
VizieR Online Data Catalog: TrES-4b RV and Ic curves (Sozzetti+, 2015)
The TrES-4 system was observed with HARPS-N on 17 individual epochs between March 2013 and July 2014. We carried out Ic-band precision photometric observations of two complete transit events of TrES-4 b with the CAHA 1.23-m on UT 2013 July 6 and UT 2014 June 30. (2 data files)
Enabling planetary science across light-years. Ariel Definition Study Report
Ariel, the Atmospheric Remote-sensing Infrared Exoplanet Large-survey, was adopted as the fourth medium-class mission in ESA's Cosmic Vision programme to be launched in 2029. During its 4-year mission, Ariel will study what exoplanets are made of, how they formed and how they evolve, by surveying a diverse sample of about 1000 extrasolar planets, simultaneously in visible and infrared wavelengths. It is the first mission dedicated to measuring the chemical composition and thermal structures of hundreds of transiting exoplanets, enabling planetary science far beyond the boundaries of the Solar System. The payload consists of an off-axis Cassegrain telescope (primary mirror 1100 mm x 730 mm ellipse) and two separate instruments (FGS and AIRS) covering simultaneously 0.5-7.8 micron spectral range. The satellite is best placed into an L2 orbit to maximise the thermal stability and the field of regard. The payload module is passively cooled via a series of V-Groove radiators; the detectors for the AIRS are the only items that require active cooling via an active Ne JT cooler. The Ariel payload is developed by a consortium of more than 50 institutes from 16 ESA countries, which include the UK, France, Italy, Belgium, Poland, Spain, Austria, Denmark, Ireland, Portugal, Czech Republic, Hungary, the Netherlands, Sweden, Norway, Estonia, and a NASA contribution
The GAPS Programme at TNG. XXVIII. A pair of hot-Neptunes orbiting the young star TOI-942
Context. Young stars and multi-planet systems are two types of primary objects that allow us to study, understand, and constrain planetary formation and evolution theories. Aims: We validate the physical nature of two Neptune-sized planets transiting TOI-942 (TYC 5909-319-1), a previously unacknowledged young star (50-20+30 Myr) observed by the TESS space mission in Sector 5. Methods: Thanks to a comprehensive stellar characterization, TESS light curve modeling and precise radial-velocity measurements, we validated the planetary nature of the TESS candidate and detected an additional transiting planet in the system on a larger orbit. Results: From photometric and spectroscopic observations we performed an exhaustive stellar characterization and derived the main stellar parameters. TOI-942 is a relatively active K2.5V star (log R'HK = -4.17 ± 0.01) with rotation period Prot = 3.39 ± 0.01 days, a projected rotation velocity v sin iâ = 13.8 ± 0.5 km s-1, and a radius of ~0.9 Râ. We found that the inner planet, TOI-942 b, has an orbital period Pb = 4.3263 ± 0.0011 days, a radius Rb = 4.242-0.313+0.376 Râ, and a mass upper limit of 16 Mâ at 1Ï confidence level. The outer planet, TOI-942 c, has an orbital period Pc = 10.1605-0.0053+0.0056 days, a radius Rc = 4.793-0.351+0.410 Râ, and a mass upper limit of 37 Mâ at 1Ï confidence level. Based on observations made with the Italian Telescopio Nazionale Galileo (TNG) operated by the FundaciĂłn Galileo Galilei (FGG) of the Istituto Nazionale di Astrofisica (INAF) at the Observatorio del Roque de los Muchachos (La Palma, Canary Islands, Spain). The authors became aware of a parallel effort on the characterization of TOI-942 by Zhou et al. (2021) in the late stages of the manuscript preparations. The submissions are coordinated, and no analyses or results were shared prior to submission
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