196,381 research outputs found
Ensemble Held-Suarez test with a spectral transform model: Variability, sensitivity, and convergence
Get PDFThe idealized test case proposed by Held and Suarez is carried out with the atmospheric general circulation model ECHAM5 of the Max Planck Institute for Meteorology. The aim is to investigate the sensitivity of the solutions of the spectral dynamical core to spatial and temporal resolution, and to evaluate the numerical convergence of the solutions. Low-frequency fluctuations at time scales as long as thousands of days are found in ultralong integrations. To distinguish the effect of changed resolution from the fluctuations caused by the internal variability, the ensemble method is employed in experiments at resolutions ranging from T31 to T159 with 16 to 81 vertical levels. Significance of the differences between ensembles is assessed by three different statistical tests. Convergence property of the numerical solution is concisely summarized by a ratio index.
Results show that the simulated climate state in the Held-Suarez test is sensitive to spatial resolution. Increase of horizontal resolution leads to slight weakening and poleward shift of the westerly jets. Significant warming is detected in high latitudes, especially near the polar tropopause, while the tropical tropopause becomes cooler. The baroclinic wave activity intensifies considerably with increased horizontal resolution. Higher vertical resolution also leads to stronger eddy variances and cooling near the tropical tropopause, but equatorward shift of the westerly jets. The solutions show an indication of convergence at T85L31 resolution according to all the three statistical tests applied.
Differences between integrations with various time steps are judged to be within the noise level induced by the inherent low-frequency variability
A graph-coloring approach to the allocation and tasks scheduling for reconfigurable architectures
No full textDesigning systems mapped onto FPGAs that foresee a dynamic reconfiguration of the application is a difficult task. It requires that the identification of the reconfigurable tasks and their allocation onto the FPGA must be defined during the design phases. Furthermore, also the schedule of dynamic reconfigurations must be defined. This paper presents an improved scheduling and allocation of reconfigurable tasks onto an FPGA, based on the coloring problem. The proposed algorithm stems from the one previously presented (Ferrandi et al., 2005), but introduces backtracking to improve the performance in terms of number of number of colors, that represent FPGAs areas. The new algorithm has been experimented on the Xilinx-based architecture defined to support dynamic reconfigurability
Historical research on the practices of care and assistance in witchcraft trials held at Poschiavo (CH) between 1631 and 1753
Get PDFThe context of Val Poschiavo has shown to be the location of numerous trials against witches in the post-Tridentine period, recognised to be a crucial era for the history of medicine and for the history of assistance, inevitably linked to the history of nursing care. Assistance is to be looked for, in this period, in the domestic settings of the population’s life, in which women exerted their caring practice.
The purpose of the research is to highlights the link between the witch hunting period in the context of Val Poschiavo and the history of assistance, comparing gestures of assistance and care of women accused of witchcraft to the modern-day basic nursing care.
The trial records of 51 women accused of witchcraft between 1631 and 1753 are examined and analysed using the historical research methodology.
Overall, 111 gestures have emerged. These were divided in gestures of care (n=51) and gestures of assistance (n=60), expressed through feeding, touch, physical proximity, words, knowledge/competence, the look and the usage of herbs.
The results allow to relate some women accused of witchcraft to caring women and offer useful groundwork to wonder about the meaning of nursing actions, with an explicit reference to the Fundamentals of Care, expression of a memory maybe forgotten, but humanly essential and indispensable
On the Testing of Vibration Performances of Road Vehicle Suspensions
No full textBoth a test rig and a method are presented for the indoor testing of vibration performances of road vehicle suspension systems. A suspension (corner) has been positioned on a rotating drum (2.6 m diameter) placed in the Laboratory for the Safety of Transport of the Politecnico di Milano. The suspension system is excited by means of cleats fixed to the working surface of the rotating drum. The forces and the moments acting at the suspension-chassis joints are measured in the frequency range 0–120 Hz. Five special six-axis load cells have been conceived, manufactured, calibrated and employed. Transient wheel motions have been recorded. The influence of the vehicle speed on the relevant vibration performance indexes has been assessed. An approach for the identification of the suspension damping characteristics is introduced. A full and accurate characterization of a vehicle suspension system has been performed
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